HRGSA BMP Project / Areawide II Handbook

 

 

 

 

 

 

 


A. Use of OP Insecticides on Tree Fruits

B. Effectiveness of OP Alternatives Against Specific Pest Problems:

            Codling Moth

            Obliquebanded Leafroller

San Jose Scale

Woolly Apple Aphid

Cherry Fruit Fly

C. Impact of OPs and OP Alternatives on Natural Enemies

D. Reducing OP Use in ‘Sensitive Areas’ 

D.1. Scenarios for Pre-Bloom Control Programs

D.2. Scenarios for Post-Bloom Control Programs

D.2.1 Seasonal Codling Moth Control With Mating Disruption Alone or Mating Disruption Supplemented By Insecticides

D.2.2 Seasonal Codling Moth Control With Different Insecticide Programs

E. Monitoring Orchards for Pests

 

 

A.  Use of OP insecticides on tree fruits. 

For many years, fruit growers in the Mid-Columbia area and elsewhere have relied on organophosphate (OP) insecticides for pest control.  Reasons for the widespread use of OPs include  effectiveness and broad-spectrum activity, low cost, grower familiarity with their performance, and lack of economical and effective alternatives.  Over time, the pest spectrum of OP insecticides has become narrower due to resistance development, which has limited their usefulness as broad-spectrum insecticides.  However, to this day OPs have remained important for control of several major pests including codling moth, leafrollers, San Jose scale, and fruit flies (Table 1). The principal uses of OP insecticides during the pre-bloom period have been for control of San Jose scale, leafrollers (primarily obliquebanded) and green fruit worm (several species).  Grape mealy bug, although present in many local pear orchards, rarely develops high enough populations to justify control.  The most widely used OP insecticide during the pre-bloom period has been Lorsban.  It is estimated that about 90% of the local tree fruit acreage was treated in 1998/99 with Lorsban at the dormant or delayed dormant stage of tree development.  On apples and pears, codling moth has been the principal target of OP sprays after bloom.  Only five years ago Guthion was the most widely used codling moth insecticide.  Use of Guthion has since decreased, primarily because of label changes such as newly established use requirements which increased the reentry period to 14 days.  Growers have many more options now for codling moth control and they increasingly rely on other methods of control such as Imidan, insect growth regulators (IGRs), other non-OP insecticides as well as mating disruption.  On sweet cherries, most OP sprays after bloom are directed against cherry fruit fly.  Seasonal control programs consist of weekly sprays of aerially applied Malathion that are sometimes preceded by ground-applied Guthion. 

Regulatory pressures are beginning to have a major impact on the continued use of OP insecticides in orchards.  There are growing concerns about exposure of agricultural workers to OP insecticides in treated orchards.  With the implementation of the Food Quality Protection Act (FQPA) these concerns are now being addressed with new use requirements for OPs and in some cases cancellations of certain uses in orchards.  In addition, water quality, specifically the presence of organophosphate pesticides in surface water, has become a major issue in the Mid-Columbia area and other fruit-growing districts in the Pacific Northwest where certain salmon, steelhead, and trout species are listed as threatened or endangered under the Endangered Species Act.  Fish are very sensitive to even low concentrations of OPs in water. 

B.    Effectiveness of OP alternatives against specific pest problems.  

Growers can only cut back on OP use if suitable alternative insecticides or other control methods are available.  Fortunately, a large number of new insecticides and alternative control methods have recently received registration and can be used as substitutes for OP insecticides.  Table 1 lists uses of OP insecticides before and after bloom and available alternatives for control of specific pest problems.  The following is a brief discussion of OP alternatives for tree fruit pests, which until recently were or are still controlled by organophosphate insecticides. Impacts on natural enemies are discussed in Section 6 C. 

Codling moth. This key pest of apples and pears is discussed first since most OP applications after bloom are directed against it.  Therefore, developing alternative seasonal control programs for codling moth will have the greatest impact on OP use on pome fruits.  Among OP alternatives with neurotoxic activity are the two pyrethroids Asana and Danitol both of which are similar to Guthion and Imidan in terms of effectiveness against codling moth (Table 2).  However, where OP resistance has developed pyrethroid insecticides may not perform as expected due to cross-resistance.  Against codling moth pyrethroids control young larvae but also eggs and adults (Table 2). Pyrethroid insecticides control a broad spectrum of pests.  However, they have not been recommended for post-bloom use on tree fruits in the Mid-Columbia due to their well-documented tendency to induce spider mite problems.  Danitol, only recently registered for use on tree fruits, is different from Asana and other ‘older’ pyrethroid insecticides in that it has miticidal activity. 

However, experience has shown that Danitol can lose its miticidal activity rather quickly (within one or two seasons) if intensively used.  Once spider mites have become resistant to Danitol it will cause resurgence and build-up of spider mites similar to other pyrethroids.  Assail is the first neonicotinyl insecticide registered for codling moth control.  Effectiveness is close to Guthion.  It controls primarily young larvae but also affects other stages (Table 2).  In addition, Assail controls leafhoppers, aphids, pear psylla and tentiform leafminer.  Caution must be employed with foliar use of Assail and other neonicotinyl insecticides since they have a tendency to stimulate spider mite build-up.  Other neurotoxic insecticides with codling moth activity are Avaunt, AgriMek and Success (Entrust is the formulation of Success for organic growers).  All three are moderately effective, control primarily young larvae and, when applied against other pests, can substitute as one of the first generation cover sprays.  However, in most situations those insecticides are not effective enough to provide seasonal control by themselves.

Several insect growth regulators (IGRs) have become available for codling moth control (Table 3).  IGRs are insecticides which interfere with the insect’s hormone system.  Their effectiveness is generally lower than that of OPs or the neonicotinyl insecticide Assail.  Dimilin, available in Europe since the 1970s for codling moth control, did not receive registration in the United States for use on pome fruits until 2002.  Dimilin primarily controls codling moth eggs and is most effective when eggs are laid on top of the residue.  Spray coverage is critical since Dimilin only affects eggs.  In areas where OP insecticides show weak performance against codling moth, Dimilin is not a good choice because of cross-resistance.  Esteem mimics the activity of juvenile hormone, which controls growth and development in insects.  Esteem primarily affects eggs and young larvae. Although Esteem has no acute toxicity to moths it has a sub-lethal effect on them and will reduce egg-laying.  Intrepid interferes with molting, controls eggs and young larvae, but has no acute toxicity to moths.  However, moths exposed to Intrepid lay fewer and less viable eggs, which is similar to effects observed with Esteem.  It is unclear, however, how these sub-lethal effects translate to control in the field.  Unfortunately, field studies suggest cross-resistance between OPs and Intrepid.    Generally, IGRs have a narrower spectrum of activity, and for that reason, are more selective to natural enemies. Because of their selectivity IGRs have a better fit with IPM programs than OPs and other broad-spectrum insecticides and are well suited to be used in combination with mating disruption and other selective control tactics. 

 

Table 1:  Current uses of organophosphate (OP) insecticides on apples, pears and sweet cherries in the

Mid-Columbia area and registered alternative controls

 

 

 

 

Target pest

OP insecticides

Alternative controls

Pre-bloom

 

 

San Jose scale

Lorsban (chlorpyrifos)

Horticultural mineral oil

 

Supracide (methidathion)

Esteem (pyriproxyfen)

 

Diazinon (diazinon)

 

Obliquebanded leafroller

Lorsban (chlorpyrifos)

Success, Entrust (spinosad)

 

 

Intrepid (methoxyfenozide)

 

 

Esteem (pyriproxyfen)

Grape mealy bug

Lorsban (chlorpyrifos)

Actara (thiamethoxam)

 

Imidan (phosmet)

Assail (acetamiprid)

 

Guthion (azinphosmethyl)

 

 

Diazinon (diazinon)

 

Post-bloom

 

 

Codling moth

Imidan (phosmet)

Assail (acetamiprid)

 

Guthion (azinphosmethyl)

Danitol (fenpropathrin)

 

 

Asana (esfenvalerate)

 

 

Intrepid (methoxyfenozide)

 

 

Dimilin (diflubenzuron)

 

 

Esteem (pyriproxyfen)

 

 

Success, Entrust (spinosad)

 

 

AgriMek (abamectin)

 

 

Avaunt (indoxacarb)

 

 

Carpovirusine, Cyd-X (CpGV)

 

 

Horticultural mineral oil

 

 

Isomate, Checkmate, NoMate, etc.

 

 

             (mating disruption)

 

 

Last Call (attract & kill)

Obliquebanded leafroller

Guthion (azinphosmethyl)

Intrepid (methoxyfenozide)

 

Imidan (phosmet)

Esteem (pyriproxyfen)

 

 

Dipel, Deliver, Javelin, MVP II, etc.       

 

 

             (Bacillus thuringiensis)

 

 

Success, Entrust (spinosad)

San Jose scale

Diazinon (diazinon)

Horticultural mineral oil

 

Guthion (azinphosmethyl)

Esteem (pyriproxyfen)

 

 

 

  Woolly apple aphid

Diazinon (diazinon)

Actara (thiamethoxam)

  Rosy apple aphid

Dimethoate (dimethoate)

 

 

 

 

  Grape mealy bug

Lorsban (chlorpyrifos)

Actara (thiamethoxam)

 

Imidan (phosmet)

Assail (acetamiprid)

 

Guthion (azinphosmethyl)

Provado (imidacloprid)

 

Diazinon (diazinon)

 

  Lygus bug, stink bug

Dimethoate (dimethoate)

Asana (esfenvalerate)

 

 

Danitol (fenpropathrin)

  Cherry fruit fly

Malathion (malathion)

Success, Entrust (spinosad)

 

Guthion (azinphosmethyl)

Provado (imidacloprid)

 

Dimethoate (dimethoate)

 

 

 


 

Table 2: Neurotoxic insecticides for codling moth control: effectiveness against codling moth and other tree fruit pests

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 Trade name

Codling moth

life stages affected *

Effectiveness

against

codling moth **

 Other pests

affected ***

 

 

 

 

 

 

Guthion (azinphosmethyl)

E

L

A

3 to 4

SJS, OBLR, GMB

Imidan (phosmet)

E

L

A

3 to 4

OBLR, GMB

 

 

 

 

 

 

Asana (esfenvalerate)

E

L

A

4

OBLR, GMB, LB, SB, PP, etc.

Danitol (fenpropathrin)

E

L

A

4

OBLR, GMB, LB, SB, PP, etc

 

 

 

 

 

 

Assail (acetamiprid)

E

L

A?

3 to 4

WALH, PP, GAA, TLM

 

 

 

 

 

 

Avaunt (indoxacarb)

E

L

A?

2 to 3

WALH, LEP

 

 

 

 

 

 

AgriMek (abamectin)

 

L

A?

2 to 3

PP, TSSM, PRM

 

 

 

 

 

 

Success, Entrust (spinosad)

 

L

A?

2 to 3

OBLR, WALH, Thrips

 

 

 

 

 

 

* E = eggs, L = newly hatched larvae, A = adult moth stage

 

 

** 4 = very effective; 3 = good control; 2 = suppression only; 1 = no to poor control

 

*** GAA = green apple aphid; GMB = grape mealy bug; LB = Lygus bug; LEP = cutworms etc.; OBLR = obliquebanded leafroller;

PP = pear psylla; PRM = pear rust mite; SB = stink bug; SJS = San Jose scale; TLM = tentiform leafminer; TSSM = twospotted spider mite complex;

WALH = white apple leafhopper

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 3: Insect growth regulators (IGRs) for codling moth control: effectiveness against codling moth

 And other tree fruit pests

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 Trade name

Codling moth

life stages

affected *

Effectiveness

against

codling moth **

 Other pests

affected ***

 

 

 

 

 

 

Dimilin (diflubenzuron)

E

 

A?

2 to 3

PP, PRM?

 

 

 

 

 

 

Esteem (pyriproxyfen)

E

L

A

2 to 3

SJS, OBLR, TLM, PP

 

 

 

 

 

 

Intrepid (methoxyfenozide)

E

L

A

3

OBLR, TLM

 

 

 

 

 

 

* E = eggs, L = newly hatched larvae, A = adult moth stage

 

 

** 4 = very effective; 3 = good control; 2 = suppression only; 1 = no to poor control

 

*** OBLR = obliquebanded leafroller; PP = pear psylla; PRM = pear rust mite; SJS = San Jose scale; TLM = tentiform leafminer

 

 

 

 

 

 

 

 

 

 

 

 

Codling moth control methods including those with a physical mode of action, microbials, and behavioral control methods are listed in Table 4. Horticultural mineral oil (HMO) acts as a suffocant against codling moth eggs but has no toxic effects on young larvae or adults. With a seasonal program of six 1% sprays (three sprays per generation) a 60 to 70% reduction in damage can be achieved.  In southern Oregon, a seasonal program of mating disruption supplemented by three 1% oil sprays applied at 200, 400 and 600-degree days from Biofix has been successfully used for control of codling moth, pear psylla, mites and other pear pests.  Although today’s summer oils are quite safe to the tree, intensive oil use may russet the fruit and can also lead to long-term yield reduction on some cultivars. Another insecticide with a physical mode of action is Surround.  This is a kaolin clay product which acts as a desiccant against young larvae but also has behavioral (i.e., repellent) effects on codling moth adults.  For lack of effective controls, Surround and similar clay products have been used some for codling moth control in organic orchards.  In conventional orchards, Surround is rarely applied against codling moth but will provide supplemental codling moth control if timing is appropriate. Surround is useful as a sunscreen to prevent sunburn, especially on apples and on red pear cultivars.

 

Table 4: Insecticides with physical mode of action, microbials and behavioral methods for codling moth

control: effectiveness against codling moth and other tree fruit pests

 

 

 

 

 

 

 

 

 

 

 Trade name(s)

Codling moth life stages affected *

Effectiveness

against

codling moth **

Other pests

 affected *** 

 

 

 

 

 

 

Omni Superior Spray, Volck

E

 

 

2

PP, TSSM, PRM, etc.

   Supreme, etc. (horticultural mineral oil)

 

 

 

 

 

 

 

 

 

 

 

Surround (kaolin clay)

 

L

A

2

PP, etc.

 

 

 

 

 

 

Dipel, Deliver, Javelin, etc.               

 

L

 

1

OBLR, other Lepidoptera

   (Bacillus thuringiensis = Bt)

 

 

 

 

 

 

 

 

 

 

 

Carpovirusine, Cyd-X

 

L

 

2 to 3

none

   (granulosis virus)

 

 

 

 

 

 

 

 

 

 

 

Isomate, Nomate, Checkmate, etc.

 

 

A

2 to 4

none

   (mating disruption)

 

 

 

 

 

 

 

 

 

 

 

Sirene (attract & kill)

 

 

A

2 to 3

none

 

 

 

 

 

 

* E = eggs, L = newly hatched larvae, A = adult moth stage

 

 

 

** 4 = very effective; 3 = good control; 2 = suppression only; 1 = no to poor control

 

*** OBLR = obliquebanded leafroller; PP = pear psylla; PRM = pear rust mite

 

 

 

 

The codling moth granulosis virus is a true microbial insecticide which is now available as two commercially available products: Cyd-X and Carpovirusine. Cyd-X must be applied with Nufilm-17 as a UV screen to slow degradation from sunlight.  The Carpovirusine formulation comes complete with a sunscreen.  To be effective, the newly hatched larvae must ingest the codling moth virus. There is no contact activity and only young larvae are susceptible.  Good spray coverage is, therefore, essential.  The codling moth virus represents a mode of action different from all other insecticides and has proven very useful for control of insecticide resistant populations in Switzerland when used in combination with mating disruption.  Drawbacks are the need for frequent applications (weekly to 10 days), the high cost, and presence of superficial damage (stings) on fruit.  However, experience has shown that use of codling moth virus over several years will result in population reduction and ultimately control.  

The endotoxin produced by Bacillus thuringiensis (Bt) is the active ingredient in commercially available Bt formulations.  The endotoxin has no contact activity to codling moth larvae and needs to be ingested to be effective.  Although young codling moth larvae are susceptible to the endotoxin, they do not ingest adequate amounts while entering fruit. None of the presently available Bt formulations provide sufficient codling moth control.

Behavioral control methods for codling moth, especially mating disruption, are being used by an increasing number of apple and pear growers in the Mid-Columbia area.  Mating disruption for codling moth control, how it works, pheromone slow-release dispensers and factors which need to be considered when using this control technology are discussed in Section 7 of this handbook.  A second behavioral control method which is commercially available is an ‘attract and kill’ product with the trade name Last Call.  This method requires the application of several hundred droplets of a sticky material which contain pheromone and the pyrethroid insecticide permethrin.  Small droplets of Last Call are measured out with a special dispenser and applied in the upper canopy of trees throughout the orchard.  Male moths are attracted to the Last Call droplets and get killed upon contact.  This control method may find a place for controlling codling moth in small home orchards or along borders in commercial orchards but has so far not been used much by growers in this area.

Obliquebanded leafroller.  Although several leafroller species are potential pests of tree fruits in the Mid-Columbia area, only the obliquebanded leafroller has consistently required annual control measures in recent years.  The Dalles sweet cherry growing district has experienced high populations since 1989.  Obliquebanded leafroller also became a serious problem on pears in 1996 in Hood River’s upper valley when growers experienced a short crop and decided to skip OP sprays, primarily Guthion, to reduce spraying costs.  In contrast to other fruit-growing areas, OP resistance in local leafroller populations does not seem to be a problem. Control measures in the spring are directed against over-wintering larvae.  Alternatives for the OP insecticide Lorsban at delayed dormant, the traditional pre-bloom control for this leafroller, are Success or the IGRs Intrepid and Esteem. In terms of effectiveness against leafroller larvae, Success and Intrepid probably provide better control than Esteem.  There is considerable latitude in terms of timing and applications can be made at cluster bud, pink or white bud and petal fall.  However, it is important that these insecticides are applied before larvae begin to pupate around mid-May.  Bt formulations such as Dipel, Deliver, Javelin, etc. are also effective against leafroller larvae but require warm weather and should therefore be used after bloom when daytime temperatures are above 65oF.  The same insecticides used against over-wintering larvae control summer larvae, which begin to appear in mid to late June depending on location. 

San Jose scale.  There are few alternatives to OP insecticides for pre- as well as post-bloom control of San Jose scale.  One alternative to OPs is a good oil program.  Trees should be thoroughly sprayed with a dilute or semi-dilute application for adequate coverage.  However, there has been little oil use after bloom because of the potential to mark fruit and damage leaves. Esteem applied with or without oil is the other choice and should be used in orchards with a well-established infestation.  Field trials have shown that Esteem applied at delayed dormant, cluster bud, pink, or at first crawler emergence in early June, is effective for controlling scale.

Cherry fruit fly.  Malathion ULV applied by aircraft is still the standard control method for cherry fruit fly in the Mid-Columbia area.  However, for the first time in many years new insecticides are available for cherry fruit fly control: Success and Provado.  Experience at the Mid-Columbia Agricultural Research and Extension Center has shown that seasonal programs of Success (applied six times at 7 to 10 day intervals) are effective for control of cherry fruit fly. Entrust is another formulation of spinosad, the active ingredient in Success, and is approved for organic production. The neonicotinyl insecticide Provado was recently registered for use on stone fruits including sweet cherries and is labeled for control of cherry fruit fly.  However, there is no experience with the use of Provado for cherry fruit fly control in the Mid-Columbia area.  If Provado is used in a cherry fruit fly control program, growers should be aware of potential spider mite build-up, especially if applied repeatedly.

C. Impact of OPs and OP alternatives on natural enemies. 

Fruit growers are all too familiar with the various insects and mites, which damage the tree, feed on leaves or injure the fruit. Collectively, we call them pests.  However, there are also many beneficial insects and mites which help to control pests.  These natural antagonists (predators and parasitoids) can play an important role in the regulation of pest populations on tree fruits.  Growers need to learn how to take advantage of the free (biological) control natural enemies can provide and how to integrate it with chemical control practices.  Relying more on biological and less on chemical control will reduce overall pesticide use in orchards, thus helping to reduce the potential for surface water contamination with pesticides.

Why has biological control not been used to its full potential on tree fruits, especially on pears?  The answer is quite simple and obvious – because of disruption by chemical pesticides.  Broad-spectrum insecticides and miticides used in conventional control programs are very toxic to most natural enemies.  Natural enemy species differ in terms of susceptibility to pesticides. Only a few of them (i.e., predatory mites) have developed a degree of resistance where they can survive applications of OP and some other pesticides.  On the other hand, generalist predators (such as predaceous plant bugs, lacewings, and lady beetles), which are key to the biological control of pear psylla and other pests, are still very susceptible to most pesticides used in today’s conventional programs in spite of many years of selection.  Tables 5 a & b summarizes information about the toxicity of commonly used orchard pesticides to key natural enemies.  Pesticides are rated from 1 to 4 in terms of their impact on natural enemies where 1 is ‘harmless’, 2 ‘moderately harmful’, 3 ‘harmful’, and 4 ‘very harmful’ (see footnotes in Tables 5 a & b for mortalities associated with each rating).  The working group ‘Pesticide Impact on Natural Enemies’ of the International Organization for Biological Control (IOBC) established this rating system as a means to categorize pesticides in terms of their harmfulness to predators and parasitoids. Our knowledge of pesticide effects on natural enemies, especially with regard to some of the newer pesticide chemistries, is still scant (Table 5a&b). One goal of the AreaWide II project is to fill some of these data gaps so growers have a better understanding of how to conserve natural enemies by making appropriate pesticide choices. The following discussion of the selectivity of orchard pesticides to natural enemies follows Table 5 a & b.  Pesticides are listed by chemical group.  Both trade names and chemical names are given. 

Amidines:

Mitac (amitraz).  Still used for pear psylla control, Mitac is somewhat selective to minute pirate bugs, lacewings and lady beetles but can be quite toxic to dipteran and hymenopteran parasitoids, spiders and predatory mites.  Information about toxicity to predaceous plant bugs is not available.

 

Carbamates:

Sevin (carbaryl): This carbamate insecticide has moderate toxicity to lacewings but is harmful to lady beetles, parasitic Hymenoptera, and predatory mites.  Information about impact on predaceous Hemiptera is lacking.

Carzol (formetanate hydrochloride): Also a carbamate, Carzol is harmful to parasitic Hymenoptera and predaceous mites.  It has low toxicity to lady beetles.  Information about toxicity to anthocorids, predaceous mirids and lacewings is lacking.

Vydate (oxamyl): The toxicity profile is similar to Carzol.  Vydate has low toxicity to lacewings but is quite toxic to predaceous mites.

 

Carboxamides:

Onager (previously known as Savey; hexythiazox): This carboxamide miticide is selective to all natural enemy groups including predaceous mites.

 

Carboxylic Acid Esters:

Acramite (bifenazate): Little is known about the selectivity of this recently registered miticide.

 

Chloronicotinyls:

Assail (acetamiprid): One of several chloronicotinyl insecticides registered for use on pome fruits, Assail is selective to spiders but may be quite toxic to predaceous mirids including Deraeocoris brevis according to recent studies.  Impact of Assail on other natural enemy groups has not been examined.

Provado (imidacloprid): The first chloronicotinyl insecticide registered on pome fruits, Provado has relatively low toxicity to pirate bugs, lacewings, parasitic Hymenoptera, and predaceous mites. 

Calypso (thiacloprid): 4. This is a promising codling moth insecticide newly registered in 2004. Calypso is harmful to minute pirate bugs.

Actara (thiamethoxam):  Toxicity to predatory mites is similar to Assail. 

 

Glycosides:

AgriMek (abamectin): This has been one of the most important pesticide products for insect and mite control on pears. AgriMek has broad-spectrum activity when it is applied.  However, surface residues are short-lived and once they move into the leaf tissue via translaminar activity treated plant tissue is relatively safe to natural enemies.

 

Insect Growth Regulators:

Dimilin (diflubenzuron): Is quite safe to spiders and phytoseiid mites but toxicity ratings to most other natural enemy groups have ranged from moderately to very harmful.

Intrepid (methoxyfenozide): This IGR is generally considered selective to most natural enemy groups.  Tests have shown that Intrepid is harmful to green lacewings.

Esteem (pyriproxyfen):  Little is known about its impact on natural enemies.  Lady beetles are susceptible and increases of certain scale pests have been noticed on citrus after applications of Esteem.

 

Organochlorines:

Kelthane (dicofol): This miticide is one of two organochlorines still used in tree fruits and is harmful to predatory mites.

Thiodan (endosulfan): Thiodan is selective to predatory mites but harmful to minute pirate bugs and moderately harmful to harmful to lacewings and lady beetles.

 

 

Organophosphates:

Guthion (azinphosmethyl):  With exception of predatory mites and spiders, Guthion is harmful to most other natural enemies.  However, some local populations of predaceous mirids and anthocorids may survive treatments of Guthion quite well possibly due to the development of resistance.

Diazinon (diazinon): The toxicity profile is similar to Guthion.

Dimethoate (dimethoate): This OP is quite toxic to most natural enemy groups including predatory mites.

Lorsban (chlorpyrifos):  Moderately harmful to lacewings and predatory mites, but harmful to very harmful to lady beetles and parasitic Hymenoptera.

Malathion (malathion): Is primarily used on cherries for cherry fruit fly control.  Malathion has short residual activity.  Therefore, to be effective against cherry fruit fly it has to be applied at frequent intervals (7 days).  Because of the frequency of use (up to seven or eight sprays per season) Malathion potentially disrupts biological control of tentiform leafminer, leafhopper and black cherry aphid.  

 

Supracide (methidathion): Is potentially harmful to very harmful to all natural enemy groups but due to timing at the dormant to delayed dormant stage most natural enemies escape its negative effects.

 

Organotins:

Vendex (fenbutatin oxide):  At lower rates Vendex is selective to predatory mites.  In general, Vendex is selective to other natural enemy groups including lady beetles and parasitic Hymenoptera.

 

Oxadiazines:

Avaunt (indoxacarb): Spiders and predatory mites survive applications of Avaunt.  Little is known about susceptibility in other natural enemy groups.

 

Pyrethroids:

The pyrethroid insecticides Asana (esfenvalerate) and Danitol (fenpropathrin) are very disruptive to natural enemies.  They are highly toxic to predatory mites and spiders as well as minute pirate bugs.  Lacewings and some parasitic Hymenoptera are slightly less susceptible.

 

Pyridazinones:

Pyramite (pyridaben):  Pyramite seems to have some selectivity to predatory mites.  Information on toxicity to various groups of generalist predators is not available.

 

Tetrazines:

Apollo (clofentizine): Similar to Onager (previously known as Savey), the miticide Apollo is quite selective to predatory mites.  One can assume that Apollo is also selective to most natural enemy groups although specific information is lacking.

 

Others:

Success, Entrust (spinosad): Lacewings seem to survive applications of Success quite well but some parasitic Hymenoptera are harmed by it.  Information about susceptibility of other natural enemy groups to Success is not available.

Omni, Volck (horticultural mineral oil): Oil is toxic to eggs of predatory mites and those of other predators. Oil has little acute toxicity to adult and mobile immature stages of most generalist predators. 

Surround (kaolin clay): Field experience has shown that this kaolin clay product can be quite toxic to natural enemies.  Predatory mites are susceptible to Surround applications, so are lady beetles and parasitic flies.

Microthiol (dry sulfur) and liquid lime sulfur: Sulfur sprays are disruptive to biological mite control. Impact on other natural enemies is probably low due to the fact that sulfur use is generally limited to the post-harvest and early pre-bloom periods.

 

Microbials:

Dipel, Deliver, Javelin, etc. (Bacillus thuringiensis; Bt): Bt formulations are generally not toxic to natural enemies since the Bt endotoxin is a stomach poison and is primarily active against lepidopterous pests such as larvae of leafrollers and various caterpillars.

Carpovirusine, Cyd-X (granulosis virus):  This virus only controls codling moth and has no activity against other pests. It is selective to all groups of natural enemies.

 

D. reducing OP use in ‘sensitive areas’

The risk of water contamination with OP insecticides is greatest in orchards located in the immediate vicinity of open water.  Areas within 100 ft of open surface water (e.g., creeks, streams, irrigation ditches, farm ponds, etc.) are considered to be ‘sensitive areas’ and growers should be particularly careful with pesticide use in those areas.  If parts of an orchard are designated ‘sensitive areas’ they should not be treated or only to a limited extent with OP insecticides. BMP practices outlined throughout this handbook should be followed in all ‘sensitive areas’.

What can growers do to prevent OP insecticides from contaminating water?  A sure way of reducing the risk of OP contamination is to cut back or altogether avoid OP use in the ‘sensitive areas’ close to open water to prevent pesticide levels from exceeding federally set limits.  Reducing OP use in the immediate vicinity of surface water is a first step.  In addition, lowering OP use on tree fruit acreage beyond the ‘sensitive areas’ should further reduce the likelihood of excessive OP levels in surface water.  Growers need to embark on a conservative approach to pesticide use based on a well-thought out and executed seasonal IPM program.  Scouting orchards for presence of pests and applying controls only when economic thresholds are exceeded is an essential part of reducing use of OPs and other pesticides.  In addition, choosing appropriate pesticides, which are not only effective against target pests but also selective to natural enemies and thereby enhance biological control, will further minimize the need for chemical interventions.  Growers need to keep in mind that the goal is not the complete elimination of OPs from their spray programs but the reduction of OP use to the point where water quality is not threatened.  To achieve that goal, it is probably safest to avoid OPs in the ‘sensitive areas’ altogether and reduce their use in the general orchard area.  The control options outlined below are examples of pre-bloom and post-bloom spray programs that eliminate or include only limited use of OPs.

D.1. Scenarios for pre-bloom control programs.  

On tree fruits pre-bloom OP use is primarily directed against San Jose scale and leafrollers.  Fortunately, alternatives are now available to achieve control of these pests without OPs.  The options listed are only suggestions and depend on pest species present and pest pressure.  Therefore, growers should consult closely with their pest control advisor about the pre-bloom control program which best fits their situation.  Applications should be made at a minimum of 200 GPA.

Low San Jose scale pressure

Apples: San Jose scale, leafroller. HMO (horticultural mineral oil; 2%) at dormant and/or delayed dormant.  Intrepid or Success at pink or petal fall followed, if necessary, by Bt (Dipel, Javelin, Deliver, etc.) against larvae of the first generation (0-30% egg hatch).

Pears: San Jose scale, pear psylla, leafroller.  HMO at dormant (beginning of pear psylla egg laying) followed by sulfur plus HMO at delayed dormant (before bud scales come off), then Esteem, Pyramite or Actara at pink.  Note: Pyramite and Actara do not help with San Jose scale or leafroller control.  In addition to pear psylla, Pyramite will also suppress pear rust mite and twospotted spider mite at the pink timing. Esteem applied at pink will suppress leafroller larvae.  Reevaluate after bloom to determine if additional leafroller controls need to be applied. 

Cherries: San Jose scale, leafroller.  HMO (horticultural mineral oil; 2%) at dormant and/or delayed dormant; Success at pink or petal fall against overwintering leafroller larvae followed, if necessary, by Bt (Dipel, Javelin, Deliver, etc.) against larvae of the first generation (applied at 0-30% egg hatch).

Moderate to high San Jose scale pressure

Apples: San Jose scale, leafroller. Apply Esteem plus HMO (2%) at delayed dormant or close to bloom (cluster bud or pink).  Use Esteem with lower rate of oil or without oil for applications close to bloom. If no Esteem was used pre-bloom apply without or with oil (1%) at first San Jose scale crawler emergence in early June. 

Pears: San Jose scale, pear psylla, leafroller. HMO (2%) at dormant (beginning of pear psylla egg-laying) followed by Esteem, sulfur plus HMO (1%) at delayed dormant; use Esteem with lower rate of oil or without oil for applications close to bloom. If no Esteem was used pre-bloom apply without or with oil (1%) at first San Jose scale crawler emergence in early June.  Add Asana plus HMO at delayed dormant if counts of overwintering pear psylla adults are high (<5/beating tray). Thiodan can be used instead of Asana. Note: Use of any pyrethroid during the pre-bloom may aggravate mite problems later on. Intrepid or Success at pink or petal fall for leafroller control followed, if necessary, by Bt (Dipel, Javelin, Deliver, etc.) against larvae of the summer generation (applied at 0-30% egg hatch).

D.2. Scenarios for post-bloom control programs. The principal target for OP sprays after bloom has been codling moth.  The alternative codling moth control programs suggested here are intended not only for the ‘sensitive areas’ but also in the general orchard area.  The idea is to reduce overall Guthion use and thereby head off the potential for water contamination with residues exceeding set limits. Two sets of alternative programs are discussed here.  One set of programs relies primarily on mating disruption for seasonal control supplemented, if necessary, by one or more insecticide applications depending on population pressure.  The other set of programs relies on different insecticide chemistries to achieve seasonal control.  What kinds of insecticides a grower chooses for these programs is determined by the severity of the codling moth problem, potential for resistance or cross-resistance, presence of other pests, selectivity to natural enemies, environmental impact, and overall IPM fit.   

D.2.1   Seasonal Codling Moth Control with Mating Disruption Alone or Mating Disruption Supplemented by Insecticides. 

Mating disruption by itself works best under very specific conditions such as very low to low population pressure, orchard area greater than 2 acres, short border relative to area, low wind conditions and relatively flat terrain.  Growers who are thinking about using mating disruption for codling moth control should consult Section 7 for a discussion of factors which need to be considered.  One of the most critical factors is the initial codling moth pressure, which determines whether mating disruption by itself is an adequate control method or whether it needs to be supplemented with one or more insecticide sprays.  Last season’s infestation levels are a good starting point.  Pack-out records often list codling moth-infested fruit as a separate damage category.  Limiting the use of mating disruption only to that part of an orchard which lies in a sensitive area is not a sound idea due to the geometry of the treated area.  Sensitive areas are generally too narrow (100 ft strips on both sides of surface water), have a long border and are not well suited for this control method.  Therefore, mating disruption should be applied to larger blocks which include the sensitive areas. 

The following are suggestions for seasonal codling moth control programs for four different initial codling moth population levels: very low, low, moderate and high. Initial codling moth pressure is defined in terms of infestation levels at harvest of the previous year.  Mating disruption is at the core of all of the suggested control programs.  When supplemental sprays are suggested, preference should be given to selective insecticides to complement the selectivity of mating disruption. Monitoring with pheromone traps is essential.  Monitoring guidelines outlined in Section 7 for mating disruption blocks should be followed.  Supplemental sprays should be applied when cumulative thresholds are exceeded (see Section 7).

Very Low codling moth pressure (<0.1% infestation in previous year). Mating disruption alone should be sufficient to provide control when applied at half to full label rate. 

Low codling moth pressure (<0.2 to 0.4% infestation in previous year).  At this codling moth pressure, mating disruption alone may not be sufficient to provide control, even when applied at full label rate.  Therefore, a supplemental insecticide spray may be necessary.  Intrepid, Esteem, Avaunt and Success are possible choices to provide supplementary control. For organic growers, a virus formulation is now available in addition to Entrust, which is the organic formulation of spinosad.  Intrepid, Esteem and Success also control leafroller larvae but codling moth timing may not be optimal for leafroller control.  Avaunt is effective on large caterpillars but not leafrollers.

Moderate codling moth pressure (0.5 to 1.4% infestation in previous year).  Mating disruption (half to full label rate) may still be used at moderate population levels but only in conjunction with additional insecticide applications.  One or two supplemental sprays may be needed when cumulative pheromone trap catches exceed thresholds.  Besides the insecticides listed for low codling moth pressure, possible choices for moderate to high-pressure situations include Assail, Imidan, Guthion, or Danitol. Note: Assail is effective against codling moth but not against other Lepidoptera and should be reserved for use later in the season against second generation when pear psylla often builds up.  Also, delaying Assail use until mid- to late summer may minimize potential spider mite build-up and negative impacts on natural enemies. The pyrethroid insecticide Danitol should be used in the same manner as Assail and its use delayed until the second generation.

high codling moth pressure (>1.5% infestation in previous year). At higher population levels, mating disruption alone, even at the full label rate, is not effective enough to maintain control.  In those situations, a full insecticide program will be needed to reduce populations to levels where mating disruption alone can again be effective.  Choices are Assail, Imidan, Guthion and Danitol.  In the lower Hood River Valley where codling moth has two generations, at least two sprays are necessary against the first and two sprays are needed against the second generation.  Due to an earlier harvest date for Bartlett pears, it may not be possible to apply more than one spray against the second generation.

D.2.2   Seasonal Codling Moth Control with Different Insecticide Programs. 

Because of topography and layout of a block, high initial codling moth pressure, or because of grower preference, mating disruption may not be the control method of choice and other control programs need to be considered.  There are many insecticide choices available to growers for codling moth control thanks to new registrations in recent years (see Tables 2, 3 & 4).  A guiding principle for designing a seasonal control program should be to alternate insecticide chemistries with different modes of action in order to ward off resistance development.  Growers should avoid using control programs built around a single chemistry, which was accepted practice with Guthion for many years.  The initial codling moth pressure determines what insecticides a grower should use in a seasonal program.  Selectivity to natural enemies should also be taken into account (Tables 5 a & b).  Unfortunately, the more selective insecticides are less effective against codling moth, and therefore, should not be used in high-pressure situations. These include Intrepid, Esteem, Avaunt, Success and AgriMek.  These insecticides should only be used when codling moth pressure is low or as supplemental sprays in alternation with more effective codling moth insecticides such as Assail, Imidan, Guthion, or Danitol. 

The following examples are control programs for low, moderate and high codling moth pressure situations.  As with mating disruption, monitoring moth flights with pheromone traps is essential so that the performance of control programs can be evaluated through the season (see 6 E, Monitoring Orchards for Pests).

Low codling moth pressure (<0.4% infestation in previous year).   Some of the weaker codling moth insecticides may provide sufficient control of the first generation.   Intrepid is a good choice for the first and/or second cover spray due to its selectivity followed by Assail and Imidan as third and fourth cover sprays, respectively, against the second generation.  The selective codling moth control program against the first generation enhances opportunities for biological control of pear psylla and other pests.  The more effective but also more disruptive codling moth insecticides Assail and Imidan are reserved for the second half of the season against the second generation when pears are also more susceptible. Assail applied in mid- to late July (third codling moth spray) will also control pear psylla, which often builds up to damaging levels at that time. 

Moderate codling moth pressure (0.5 to 1.4% infestation in previous year).  With increasing codling moth pressure, control of the first generation needs to be strengthened by using more effective insecticides.  Therefore, a stronger insecticide such as Imidan should follow Intrepid to finish out the control program against the first generation.  The control program against the second generation could again consist of Assail followed by Imidan.  

High codling moth pressure (>1.5% infestation in previous year).  In high-pressure orchards growers need to resort to ‘stand-alone’ insecticides which are capable of providing economic control if used by themselves in a seasonal program. The OPs Imidan and Guthion, the chloronicotinyl Assail and the pyrethroid Danitol fall into this category.  Guthion should be used at a time when the long reentry period of 14 days does not interfere with other orchard activities.  It is suggested to alternate insecticides from the different chemical classes.  For instance, the first cover could be Guthion followed by Imidan as the second cover spray, then Assail as the third cover spray and Danitol as the fourth cover spray.       

E. Monitoring Orchards for Pests

Orchard monitoring for pest populations or damage is a fundamental component of most IPM programs.  A full treatment of this topic is, however, beyond the scope of this handbook.  A monitoring program for codling moth in mating disruption programs is outlined in Section 7.  Orchard Pest Monitoring Guide for Pears: a resource book for the Pacific Northwest provides an in depth source of information on pest monitoring in pear orchards.  Orchard Pest Management: a resource book for the Pacific Northwest provides a complete source of information on orchard IPM.  Both publications are available from the Good Fruit Grower (800) 487-9946 and http://goodfruit.com/.