In response to regulatory pressures, pest management in orchards will become more challenging and risky for producers. As federal and state regulations restrict the use of, or phase out, the organophosphate insecticides, producers must reduce their reliance on what may be considered as the most effective insecticides that we have ever had. Case in point is the phase-out of azinphos-methyl (Guthion) in apples and pears by 2012. Large-scale research/producer projects like the 5-year Areawide Codling Moth Integrated Pest Management Project in the western United States demonstrated that the key insect pest can be controlled without organophosphates, but the transition was not easy for participating producers, and there was a steep learning curve.
Organophosphate insecticides are broad-spectrum products effective against many insects, multiple life stages of pests, and have a relatively long period of residual activity. Applying an organophosphate was like playing Wiffle ball with a beach ball; your timing and aim may be off, but you can still hit the target with the bat. Spray a little azinphos-methyl a couple weeks after apple bloom, and you could kill off adult moths and count on the residue to knock off any hatching larvae for the next couple weeks. That same application would also reduce populations of leafrollers, bugs, aphids, and other insect pests.
While there are many alternative products for controlling codling moth, they all target a narrower spectrum of insects. Now, growers must replace that beach ball with a wiffle ball. A leading alternative to azinphos-methyl for codling moth control is mating disruption. Mating disruption with sex pheromone lures is effective only on the male moth and toxic to nothing else. With mating disruption, growers must consider the risk from codling moth pressure from outside the orchard as well as inside. Another alternative, the granulosis virus products, are specific to codling moth, effective only on the larval neonates, and have relatively short periods of residue activity. Not only must the grower’s spray timing be concurrent with peak emergence of larvae from the eggs, but the grower has to swing that wiffle bat multiple times to hit a smaller ball.
In anticipation of losing azinphos-methyl in the near future, growers need to experiment or practice with alternative products this season. Lists of alternative products for codling moth can be found in any of the university’s crop guides or management handbooks.
These alternative products are not recommended until university researchers have data that demonstrates product efficacy. Nevertheless, grower practice with the new products and control strategies is required, as there will be a steep learning curve in aiming and hitting your target pest.
Growers need to remain on guard against anticipated setbacks and control failures. To offset this risk, growers will have to spend more time and effort monitoring and scouting their orchards to assess the effectiveness of their management programs during this transition period. On the plus side, there are opportunities for increased biological control of secondary pests in orchards free of broad-spectrum insecticides. Furthermore, the industry can continue to promote our fruit as the safest produce in the world, our orchards as safer places to work, and our management practices as more environmentally friendly than
This issue of Good Fruit Grower emphasizes the work being done through research, extension, and improved grower management practices to keep up with our industry’s ever-changing pest control procedures. It’s a tremendous effort—and every grower needs to be
a part of it.