Brandenburg and Herbert Insect Control Article in v-C Peanut News

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Managing thrips and tomato spotted wilt in peanut in the absence of Temik

Ames Herbert and Sean Malone, Virginia Tech

Rick Brandenburg and Brian Royals, North Carolina State University

The loss of Temik necessitates finding effective and economic alternatives for peanut farmers. Temik was highly effective in reducing thrips numbers, minimizing plant damage caused by direct thrips feeding, and reducing incidence of tomato spotted wilt virus transmission by thrips. Temik’s replacement, a similar product called Memik (MEY Corporation USA), was not available in 2012 and will not be available in 2013 or likely 2014 (according to various sources). The other legal in-furrow options for thrips management in peanut in the Virginia/Carolina area are Orthene (or Acephate) (there are label issues in Virginia), Admire Pro and Thimet 20G. Most notably, a seed treatment that we have been testing from Syngenta for several years has been released (on a limited basis in 2012) as CruiserMaxx Peanut Custom Blend—Powder, and is showing promise.

We have been field testing these and other products on research farms and growers’ fields. Results from these trials indicate most of these options can be effective in reducing thrips populations, thrips injury to plants, incidence of tomato spotted wilt, and resulting in yields that can equal previously labeled standards like Temik. Each offers some advantages. For example, Orthene (Acephate) and Admire Pro are compatible with other liquid in-furrow applied products such as fungicides and/or seed inoculants which would help limit the number of field trips. CruierMaxx Peanut offers the convenience of a seed treatment—no mixing, handling, or application hassles. Thimet has the advantage of fitting those growers who prefer a dry, flowable granular in-furrow option.

However, we are also seeing some drawbacks to these options. Peanut research conducted in 2011 in Virginia and North Carolina has shown poor seedling emergence and reduced plant stand associated with at-planting, liquid in-furrow applications of Orthene (Acephate). This problem occurred with both 12 and 16 oz rates across several varieties, and was reported by numerous growers. The plant losses were severe enough to result in reduced pod yields. In 2012 we investigated this further by evaluating liquid in-furrow applications of Orthene 97 @ 8, 12, and 16 oz/acre and Admire Pro @ 7, 8.5, and 10.5 oz/acre. Thimet 20G @ 3.5 and 5 lb/acre and Temik 15G @ 7 lb/acre were included for comparison. Although liquid in-furrow Orthene (Acephate) treatments reduced stands compared with the other treatments, the problem was not as severe as in 2011 and yields were not affected.

Our trials with Admire Pro, have shown performance that is somewhat variable across the tests in the two states. In some cases thrips control and yields have been excellent. In other trials Admire Pro performance has been more moderate. Some of this variability may be due to differences in weather conditions, soil types and degrees of thrips pressure. These are all issues that more field testing and experience may help explain.

This performance variability issue also appears to be the case with CruiserMaxx Peanut. For example, in some research plots, these seed treatments have provided more than adequate levels of thrips control, reduced incidence of tomato spotted wilt, and usually (but not always) resulted in top yields equal to Thimet. In a large replicated on farm trial in Virginia, Trilex Optimum seed treatment with Thimet @ 5 lb/acre was compared with CruiserMaxx Peanut Custom Blend—Powder seed treatment. Thrips injury ratings were lower in the Thimet treatment and yields were higher.

Conclusions from this work indicate that although there are several options that show promise for ‘replacing’ Temik for thrips control in peanut, there is still some variability in how they perform over years and locations. Our recommendations to growers are to 1) pick the delivery system that best suits their farm operation whether it be liquid in-furrow, seed treatment, or in-furrow granular, then 2) back it up with a post-emergence foliar application of Orthene (Acephate) @ 4 – 6 oz/acre broadcast at late ground-cracking unless thrips injury is very light.

As we move forward, our challenge will be to continue working to see what might be done to further improve and stabilize the performance of these options, given that Temik will not be available in the short term, and perhaps will never return. The current control recommendations are not “bad” and in fact, much of the time these other products perform as well as Temik. The main difference is the consistency from one year to the next, which was always Temik’s strong point.

Thrips control options for peanut in Virginia and North Carolina, 2013

Application technique Material Pros Cons
Granular in-furrow Thimet 20G Good thrips control; reduces tomato spotted wilt virus Causes some leaf burn; needs an overspray; 3.5-5 lb/acre application rate
Liquid in-furrow Orthene or Acephate 97 Good to excellent thrips control; can be tank mixed with fungicides/inoculants Label issues in Virginia; delayed seedling emergence/reduced stand may occur; needs an overspray
Admire Pro Good thrips control; can be tank mixed with fungicides/inoculants Variable; needs an overspray
Seed treatment CruiserMaxx Peanuts Custom Blend Powder Good thrips control Limited availability; variable; needs an overspray
Foliar broadcasts, alone Several options are available Fair to good thrips control under low to moderate thrips pressure Must make two applications; not sufficient under heavy thrips pressure

Article first appeared as North Carolina Peanut Note (PNNC-2013-002)