Time to buckle down rather than give up on controlling oriental fruit moth in peaches

Here’s answers to your questions on using mating disruption and pyrethroid insecticides in controlling oriental fruit moth in Michigan peaches.

Oriental fruit moth has become an increasing concern across much of the peach industry in recent years. The solution to this problem will take the united effort of the peach industry recommitting to some important standards as a unit to bring oriental fruit moth population numbers back down into a reasonable range. We can get this problem back under control, but it will take a team effort on all of our parts.

Two concerns that have bothered growers over the past couple of years are as follows.

“I’m not seeing control of oriental fruit moth with my mating disruption like I it used to, especially at block edges.”

You’re absolutely right. However, this is not because mating disruption doesn’t work anymore, it’s because we have had an explosion in the populations of oriental fruit moth in area orchards. This is due to reduced use of oriental fruit moth mating disruption by the industry as a whole and over-reliance on pyrethroid insecticides. The result is oriental fruit moth damage the likes of which we have never seen as an industry.

Please read Larry Gut and Mike Haas’ new Michigan State University Extension article on mating disruption strategies for information on proper choice of mating disruption product and timing of applications before the growing season starts: “Manage oriental fruit moths using mating disruption.”

This information will be critical for getting back to where we want to be as an industry.

“Our chemistries don’t work like they used to.”

In the case of pyrethroid insecticides, this is likely true. Pyrethroid resistance for oriental fruit moth has been documented in adjacent states and in Ontario. Strict reliance on these products is bound to get us in trouble with resistance, and preliminary information from Gut’s lab suggests this may already be the case in our area. The good news: There are still many products on the market we know work very well on oriental fruit moth that do not fall in the pyrethroid class. These products are critical in maintaining any action we have left from the pyrethroid class while avoiding economic hardships caused by loss of crop.

Considerations for 2017

Pyrethroid usage for oriental fruit moth management. Due to the reduced cost associated with using pyrethroid-based spray programs for oriental fruit moth management, many growers rely on these products exclusively in their spray programs. However, preliminary data from Gut tells us we are likely starting to lose pyrethroid efficacy on oriental fruit moth, contributing to the pressure we’ve experienced recently. There are several lessons to be learned here.

  • A cheap pyrethroid spray that is not working at high efficiency should not be considered more economical than a more expensive product that does. We work too hard as an industry to be spending money on products that are providing sub-par control, and there is a good chance several of the pyrethroid products now fit this description (see Table 2 below).
  • We still have many products we know are effective in managing this insect (see Table 1). Do yourself, as well as your neighbors, a favor and put something besides strictly pyrethroids out there this year. Rotating active ingredients in products has always been important, but it is particularly important for oriental fruit moth right now.
  • Keep your spray intervals tight, particularly if you do choose to use pyrethroids. Pyrethroids can break down quicker in hot weather, and gaps in coverage could mitigate what management we still do get with these products. This year, spray a rotation of active ingredients at tight windows in the presence of mating disruption.
  • Use pheromone traps to monitor oriental fruit moth population levels. This is one of the best ways to get an indication of the pressure a peach block is facing from oriental fruit moth and the potential for damage. Catches for the first generation will show what is carried over from last year. Catches for the second and third generations help to indicate how effective the spray program is for the current year.
  • Non-bearing peach orchards still need to be protected from at least the first generation of oriental fruit moth.
  • Pyrethroids may still have some value for helping to control tarnished plant bug.

Table 1 summarizes non-pyrethroid product efficacy towards oriental fruit moth, compiled from information presented by Gut. Re-familiarize yourself and your staff with this list before we get into the growing season.

Table 1. Insecticides registered for oriental fruit moth control in peach

Compound trade name

Chemical class

Effectiveness

Residual activity

Imidan

OP

Excellent

14 days

Exirel

Diamide

Excellent

10-14 days

Altacor

Diamide

Excellent

10-14 days

Delegate

Spinosyn

Excellent

7-10 days

Assail

Neonicotinoid

Excellent

10-14 days

Rimon

IGR

Excellent

10-14 days

Voliam Flexi

Premix

Excellent

10-14 days

Intrepid

IGR

Good

10-14 days

Diazinon

OP

Good

10-14 days

Avaunt

Oxadiazine

Fair

7-10 days

Lannate

Carbamate

Fair

7-14 days

Sevin

Carbamate

Fair

7-14 days

Esteem

IGR

Fair

7-10 days

Table 2 summarizes the products that are at risk of no longer being effective. We need to break the cycle of repeated pyrethroid use in the 2017 growing season due to growing concerns of resistance. Remember, your spray guide says “excellent” on these products right now, but work done in 2017 on toxicity of these products on oriental fruit moth may update these ratings considerably. Until 2017 data is available, play it safe and either rotate with other modes of action or avoid these products entirely.

Table 2. AT RISK insecticides registered for oriental fruit moth control in peach

Compound trade name

Chemical class

Current labelled effectiveness rating

Residual activity

Asana

Pyrethroid

Excellent

7-10 days

Danitol

Pyrethroid

Excellent

7-10 days

Lambda-Cy

Pyrethroid

Excellent

7-10 days

Baythroid

Pyrethroid

Excellent

7-10 days

Perm-up

Pyrethroid

Excellent

7-10 days

Leverage

Premix

Excellent

10-14 days

Endigo

Premix

Excellent

10-14 days

Voliam Xpress

Premix

Excellent

10-14 days

Lastly, don’t get discouraged if you see high numbers of oriental fruit moth this year again. This problem likely took several years to get this bad, and it may take a couple of years to bring the population back down. It only takes a few orchards worth of improperly managed peaches scattered around your region to help this pest maintain the population levels we are seeing. We’ve also had an extremely mild winter, which may mean a particularly high rate of successful overwintering for the insect. If everyone counts on their neighbor to do the right thing and use mating disruption and rotate non-pyrethroid sprays this year, we all lose. We’re a team here, so let’s all commit to updating our programs in order to move forward in 2017.

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