HRGSA BMP Project / Areawide II Handbook
A. Use of OP Insecticides on Tree
Fruits
B. Effectiveness of OP
Alternatives Against Specific
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
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
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Table 1:
Current uses of organophosphate (OP) insecticides on apples, pears and
sweet cherries in the |
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Mid-Columbia area and registered alternative controls |
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Target pest |
OP insecticides |
Alternative controls |
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Pre-bloom |
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San Jose scale |
Lorsban (chlorpyrifos) |
Horticultural mineral oil |
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Supracide (methidathion) |
Esteem (pyriproxyfen) |
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Diazinon (diazinon) |
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Obliquebanded leafroller |
Lorsban
(chlorpyrifos) |
Success, Entrust (spinosad) |
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Intrepid (methoxyfenozide) |
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Esteem (pyriproxyfen) |
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Grape mealy bug |
Lorsban (chlorpyrifos) |
Actara (thiamethoxam) |
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Imidan (phosmet) |
Assail (acetamiprid) |
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Guthion (azinphosmethyl) |
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Diazinon (diazinon) |
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Post-bloom |
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Codling moth |
Imidan (phosmet) |
Assail (acetamiprid) |
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Guthion (azinphosmethyl) |
Danitol (fenpropathrin) |
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Asana (esfenvalerate) |
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Intrepid (methoxyfenozide) |
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Dimilin (diflubenzuron) |
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Esteem (pyriproxyfen) |
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Success, Entrust (spinosad) |
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AgriMek (abamectin) |
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Avaunt (indoxacarb) |
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Carpovirusine, Cyd-X
(CpGV) |
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Horticultural mineral oil |
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Isomate, Checkmate, NoMate, etc. |
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(mating disruption) |
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Last Call (attract & kill) |
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Obliquebanded leafroller |
Guthion
(azinphosmethyl) |
Intrepid (methoxyfenozide) |
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Imidan
(phosmet) |
Esteem (pyriproxyfen) |
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Dipel, Deliver, Javelin, MVP
II, etc. |
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(Bacillus thuringiensis) |
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Success, Entrust (spinosad) |
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San Jose scale |
Diazinon (diazinon) |
Horticultural mineral oil |
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Guthion (azinphosmethyl) |
Esteem (pyriproxyfen) |
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Woolly apple aphid |
Diazinon (diazinon) |
Actara
(thiamethoxam) |
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Rosy apple aphid |
Dimethoate (dimethoate) |
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Grape mealy bug |
Lorsban (chlorpyrifos) |
Actara (thiamethoxam) |
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Imidan (phosmet) |
Assail (acetamiprid)
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Guthion (azinphosmethyl) |
Provado (imidacloprid) |
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Diazinon (diazinon) |
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Lygus bug, stink bug |
Dimethoate (dimethoate) |
Asana (esfenvalerate) |
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Danitol (fenpropathrin) |
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Cherry fruit fly |
Malathion (malathion) |
Success, Entrust (spinosad) |
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Guthion (azinphosmethyl) |
Provado (imidacloprid) |
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Dimethoate (dimethoate)
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Table 2: Neurotoxic
insecticides for codling moth control: effectiveness against codling moth and
other tree fruit pests |
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Trade name |
Codling
moth life
stages affected * |
Effectiveness
against
codling
moth ** |
Other
pests affected
*** |
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Guthion (azinphosmethyl) |
E |
L |
A |
3
to 4 |
SJS, OBLR, GMB |
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Imidan (phosmet) |
E |
L |
A |
3 to 4 |
OBLR, GMB |
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Asana (esfenvalerate) |
E |
L |
A |
4 |
OBLR, GMB, LB, SB, PP, etc. |
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Danitol (fenpropathrin)
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E |
L |
A |
4 |
OBLR, GMB, LB, SB, PP, etc |
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Assail (acetamiprid) |
E |
L |
A? |
3
to 4 |
WALH, PP, GAA, TLM |
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Avaunt (indoxacarb) |
E |
L |
A? |
2
to 3 |
WALH, LEP |
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AgriMek (abamectin) |
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L |
A? |
2
to 3 |
PP,
TSSM, PRM |
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Success, Entrust (spinosad) |
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L |
A? |
2
to 3 |
OBLR, WALH, Thrips |
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* E = eggs, L = newly hatched
larvae, A = adult moth stage |
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** 4 = very effective; 3 = good
control; 2 = suppression only; 1 = no to poor control |
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*** GAA =
green apple aphid; GMB = grape mealy bug; LB = Lygus bug; LEP = cutworms etc.;
OBLR = obliquebanded leafroller; |
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PP = pear psylla;
PRM = pear rust mite; SB = stink bug; SJS = San Jose scale; TLM = tentiform leafminer; TSSM = twospotted spider mite
complex; |
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WALH = white apple leafhopper |
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Table 3: Insect growth regulators
(IGRs) for codling moth control: effectiveness
against codling moth |
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And other tree fruit pests |
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Trade name |
Codling
moth life
stages affected
* |
Effectiveness
against
codling
moth ** |
Other
pests affected
*** |
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Dimilin (diflubenzuron) |
E |
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A? |
2
to 3 |
PP,
PRM? |
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Esteem (pyriproxyfen) |
E |
L |
A |
2
to 3 |
SJS, OBLR, TLM, PP |
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Intrepid (methoxyfenozide)
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E |
L |
A |
3 |
OBLR, TLM |
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* E = eggs, L = newly hatched
larvae, A = adult moth stage |
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** 4 = very effective; 3 = good
control; 2 = suppression only; 1 = no to poor control |
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*** OBLR
= obliquebanded leafroller;
PP = pear psylla; PRM =
pear rust mite; SJS = San Jose scale; TLM = tentiform leafminer |
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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.
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Table 4: Insecticides with
physical mode of action, microbials and behavioral
methods for codling moth |
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control: effectiveness against
codling moth and other tree fruit pests |
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Trade name(s) |
Codling
moth life stages affected * |
Effectiveness against codling
moth ** |
Other
pests affected *** |
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Omni Superior Spray, Volck |
E |
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2 |
PP,
TSSM, PRM, etc. |
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Supreme, etc. (horticultural mineral oil) |
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Surround (kaolin clay) |
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L |
A |
2 |
PP,
etc. |
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Dipel, Deliver, Javelin, etc. |
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L |
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1 |
OBLR, other Lepidoptera |
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(Bacillus thuringiensis = Bt) |
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Carpovirusine, Cyd-X |
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L |
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2
to 3 |
none |
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(granulosis virus) |
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Isomate, Nomate,
Checkmate, etc. |
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A |
2
to 4 |
none |
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(mating disruption) |
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Sirene (attract & kill) |
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A |
2
to 3 |
none |
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* E = eggs, L = newly hatched
larvae, A = adult moth stage |
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** 4 = very effective; 3 = good
control; 2 = suppression only; 1 = no to poor control |
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*** OBLR
= obliquebanded leafroller;
PP = pear psylla; PRM =
pear rust mite |
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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
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.
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
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
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