Apple and Pear Biological Control


PO Box 1555, Ventura, CA 93002

800-248-2847  *  805-643-5407

fax 805-643-6267



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A successful IPM program in orchards will utilize many cultural practices such as proper irrigation to maintain leaf temperature, kaolin-clay barriers, mating disruption and trapping, as well as beneficial insect releases.  The following are general guidelines for augmenting insect diversity to control the common pests found in Washington apple growing regions.  See WSU Tree Fruit Research and Extension Center for complete management strategy. 


Mite Control:

The western predatory mite, Galendromus occidentalis, is ideal as it is a predator of all common mite pests in orchards, tolerant of hot, dry conditions, and resistant to many pesticides (contact us with compatibility questions).  Release 2,500-5,000 per acre early in the season at the first sign of spider mites using the presence-absence sampling method.  Continue sampling and repeat in 1-2 months if control is not achieved. 

For hot spots, use the Spider Mite Destroyer ladybeetle, Stethorus punctum.  It has been effective in controlling mites in Pennsylvania apple orchards and released in raspberries and hops in central Oregon with good results.  Release 20 Stethorus per infected tree in hot spots.  They will remain in the trees as long as mites are present, and then move into the environment.  If mites return, they will follow them back into the trees.  Green lacewing (see below) will also aid in mite control.


Aphid Control:

Natural parasites and predators of aphids are common in organic orchards.  Insecticides are detrimental to these and should not be necessary with an IPM program including monitoring and preventative releases of beneficial insects. 

The aphid predatory midge Aphidoletes aphidimyza works extremely well in orchards.  The larval stage is a general aphid predator and the adult midge will disperse throughout the orchard laying eggs in areas of high pest density.  Two weekly introductions of 10,000 per acre will establish for numerous years.  They can be generally applied on the windward side, or, even better, 5,000 applied generally on the windward side, at dusk, and the rest applied in effected trees.

Green lacewing, Chrysoperla carnea and C. rufilabris, larvae are general predators that will eat 200 aphids or pest eggs during their two-week larval stage.  The adults feed on pollen and nectar, and have great dispersal ability.  Female adults will lay hundreds of eggs close to sources of prey for the larvae.  Repeated releases, ant control, and providing food sources for the adults are critical for successful implementation of lacewing in an IPM program.  Use at a rate of 5,000-10,000 per acre every two weeks for 2-4 releases or until control is achieved. 

Cover cropping with corn, sudan grass, and beneficial ‘insectary’ plantings will greatly enhance biological control by forming banks of parasitized aphids and nectar food sources for the adult predators. 




Codling moth:

The lepidoteran egg parasite Trichogramma platneri is a U.S. native recommended for western trees.  Release 100,000 per acre for three consecutive weeks as soon as moths are detected in traps.  Can be used in conjunction with a mating disruption program.

For larval control, use Cyd-X granulovirus, spinosad or Bt sprays timed according to moth flight and degree-day calculations. 



Conservation of natural enemy complexes is the critical factor in controlling leafroller populations.  Many natural occurring parasites attack this pest.  Green lacewing releases are beneficial and the use of non-disruptive pesticides such as Bt or spinosad. 



Thrips are controlled by conserving natural predators and augmenting with releases of the general predator green lacewing as described before. 


The keys to effective biological control are starting early and regular monitoring.