The Case for Biological Pesticides for Soybeans

An article titled “Biological pesticides may pull integrated pest management out of a bog” by John Hart appeared in the Nov. 1, 2017 online edition of Southeast Farm Press. The lead sentence in that article states “Biological pesticides can play a key role in a successful integrated pest management (IPM) program and can be useful in increasing sustainability on the farm.” Also in that article, David Epstein, senior entomologist with USDA’s Office of Pest Management Policy, states “IPM includes everything. You can use biopesticides in an IPM program. IPM is not limited to one approach. It takes everything into consideration. IPM is applicable across all farming systems. It is a philosophy of pest control formed on principles of ecology.”

All farming systems, whether they be organic or non-organic, use pesticides. In today’s non-organic farming environment that is dealing with pesticide resistance development to synthetic pesticides in both fungal pathogens and insect pests, the role and development of biopesticides should be explored in-depth to determine efficacy and economic potential.

Several “biological insecticides” are presently labeled for use on commodity crops (e.g. soybean). Examples are Agree, Biobit, Dipel, Javelin, Heligen, and Dimilin. These insecticides do not poison the pest; rather they kill by causing a disease, as in the case of Bacillus thuringiensis (Bt) (e.g. Agree –IRAC code 11A) and Helicoverpa zea nucleopolyhedrovirus–HzNPV (e.g. Heligen), or a physiological dysfunction (Dimilin–IRAC code 15). These products are particularly suited to use in pest management operations because they have little or no effect on natural enemies of the pest or beneficial insects such as bees. Because of their mode of action, use of these compounds does not result in a quick kill. Thus, it may be several days after application before the insect is killed. However, little or no feeding by the pest will occur during this period.

After exploring the labels of the above bio-insecticides, “For Organic Production” is stated in plain view on p. 1 of each label. However, perusal of subsequent pages of the labels shows that they target many of the lepidopteran insect pests that plague soybean–e.g. loopers, green cloverworm, saltmarsh caterpillar, velvetbean caterpillar, and armyworms (Bt insecticides), and corn earworm and tobacco budworm (HzNPV)–and are in fact labeled for use on soybeans. Thus their use is not restricted to organic production systems.

In an earlier blog, I reported on the registration of the biological fungicide Serifel that is labeled for use on specialty crops or in an organic program, but not for commodity crops such as soybean (i.e., soybean is not specified anywhere on the label). In that article, I asked the question “Why did the developing company not work toward a label for Serifel or a similar biological fungicide to target fungal pathogens of commodity crops?”

So how do we get these biopesticide products labeled or thoroughly evaluated for use in soybean IPM programs? I don’t have the answer because the companies that develop these products and submit their registration application to the US-EPA determine the label contents and use directions, and indicate the crops they are labeled for when they submit the application, or when they submit a request to add a new use to an existing product label. Thus, soybean producers depend on these companies to label allowed crops and/or provide efficacy data that support the effectiveness of these biopesticides on those crops. Since private companies are the only source of biopesticide products and developments, the question at the beginning of this paragraph is one that commodity groups should be asking them.

All sectors (both public and private) of the US agricultural support system should be working diligently to ensure that all available tools for IPM are available and/or effective for use in all crops. And since it is obvious that efficacious biopesticides can be one of those tools, they should be available to producers of both organic and commodity crops. This will support the long-term sustainability of the large commodity crop production sector in this country. It should be obvious to all that these tools are especially needed where resistance to synthetic pesticides has developed and is continuing to develop in the insect pests and disease pathogens that negatively affect soybean production.

So let’s revisit the gist of the quotes in the opening paragraph of this article. Yes, biological pesticides can–and should–play a role in integrated pest management (See the 2017 UAEX Insect Control Guide–p. 108, 112, 115, and 118). And yes, biopesticides can–and should–be an integral part of an IPM program, especially where resistance to synthetic pesticides has developed. And yes, IPM is applicable across all farming systems. However, until biopesticides are thoroughly evaluated for efficacy against pests that affect commodity crops such as soybean, producers will not fully utilize them if they have little or no information about their performance when used as a component of their IPM strategies. Plus, the cost of these products should be weighed against their potential effectiveness as a component of an IPM program.

Finding answers to questions regarding the use of biopesticides as a component of IPM for commodity crops such as soybean should receive increased attention from both the private and public research sectors.

Composed by Larry G. Heatherly, Nov. 2017, larryheatherly@bellsouth.net