Corn harvest is getting into full swing and we are getting questions on grain protectants. Here is a quick update from Michael Toews, UGA Entomologist :
Grain protectants, insecticides labeled for application to raw grain, are intended to prevent stored grain insect infestations as opposed to treating existing infestations. These products should not be applied before sending grain through the drier or immediately after coming out of the drier as the high heat would quickly degrade the insecticide. Grain protectants should only be applied to cool grain that is of proper storage moisture with minimal dockage and fines. It is best to apply protectants at the bottom of the auger so the insecticide can thoroughly coat the kernels as they are conveyed up the auger. The secret to using protectants it to get good coverage on as many kernels as possible! If an infestation is present, fumigation is the only method of preventing further damage.
Grain protectants are covered under the heading “stored product insect management” (pp. 529-531) in the 2014 commercial edition of the Georgia Pest Management Handbook. Protectants that are listed and currently available for use on stored corn include Actellic 5E, Centynal and Diacon II. Sensat and Execute will not be available this year and neither Tracer nor Tempo SC is labelled for use on stored grain.
Actellic 5E (9.2-12.3 oz per 1000 bu) is expensive, but a top performer in our tests. This product gives good protection from weevils and is widely available at distributors. Using the higher rate gives longer residual.
Centynal (8.53 oz per 1000 bu) is less expensive than Actellic, but we don’t much efficacy data to compare. It looks good in preliminary tests and data from other states. Georgia customers can order by calling the Degesch America Inc. at 804-231-1000. Their website is https://www.bugfreegrains.com/.
Diacon II (1.75 to 14 oz per 1000 bu) is also relatively inexpensive, but it will not control maize weevils or lesser grain borers. Diacon II at 7 oz is a good tankmix partner with Centynal to give excellent control of all stored product moths and beetles. Georgia customers can order by calling Degesch America Inc. at 804-231-1000.
Finally, appropriate use of aeration to cool the grain is an important part of any stored grain management program. Cool grain will greatly increase the generation time of stored grain insects, while increasing the residual activity of the grain protectant.
Thanks for your time,
Jeremy M. Kichler
University of Georgia Cooperative Extension
County Extension Coordinator