Grain Protectants and Top-dress Treatments for Stored Grains

Introduction

Protecting grain in storage is important to maintain the grain quality for the best economic gain. Preparing storage structures prior to harvest is important. There are multiple steps to ensure that grain quality is preserved. Sanitation through cleaning equipment that will be in contact with new grain is essential. This includes storage structures, grain handling equipment and transportation vehicles. It is also necessary to keep the area surrounding storage structures free of vegeta-tion and spilled grain. Maintenance of equipment is critical to safeguard that all equipment is functioning properly, and the storage structure is sealed to prevent moisture and insects from entering. Insecticides for the treatment of empty-structures and surrounding perimeters aid in controlling insect activity and minimize initial insect infestations. More information can be found on these topics in fact sheet BAE-1112, Preparing Grain Bins and Flat Storages Prior to Harvest or Incoming Product Storage.

 

In Oklahoma, insect populations will gradually increase in grain stored after harvest if the grain is not protected. Stored grain insect pests have a maximum rate of population increase when the grain temperature is 77 to 90 F. Populations will continue to grow during the summer, reaching a peak number of insects in the fall before temperatures begin to cool and the temperature of the grain lowers. Grain protectants will eliminate or at least minimize the amount of insect population growth. The earlier the insect population growth can be delayed, the better. 

 

Grain Protectants

The cleaner the grain is when being stored, the fewer problems there will be in the future. Grain quality never improves with storage, so the goal is to maintain grain as near to harvest quality as possible. Grain protectants help in preserving the quality of the grain from insect damage. Grain protectants are insecticides applied to the grain as it is being loaded into the storage structure. Apply the insecticide to a moving grain stream at the bottom of the bucket elevator, auger or belt to ensure the insecticide comes into contact with as many grain kernels as possible while the grain is moving to its final destination. Table 1 shows a list of insecticides labeled for use as grain protectants.

 

Most grain protectants are applied to the entire grain mass. However, a few products allow for an alternative treatment where the insecticide is only applied to certain layers of the grain mass. One method is to treat only the top 2 to 3 feet of grain. Another method is to treat only the bottom and top layers of the grain mass. The last method is to treat the bottom layer of grain, every fifth load and the top layer, if the structure is large enough to accommodate multiple loads of grain. Please read the label carefully to see if the product allows for layer treatments. Products labeled for the option of layer treatments are noted in Table 1.

 

Top-Dress Treatments

Many of the grain protectants also can be used as a top-dress treatment where the insecticide is applied to the grain surface to prevent insect infestation from occurring from the top of the structure. In most cases, the insecticide is incorporated into the top four inches of grain, but one product requires mixing the product to a grain depth of 1 foot from the top surface. A few insecticides are applied to the grain surface without mixing. Two insecticides are applied in two stages, where the first half of the calculated amount of product is applied and incorporated, then the second half is applied to the grain surface and left undisturbed. A list of insecticides labeled for top-dress treatments can be found in Table 2.

 

Insecticide Application

It is the law to read the insecticide label and follow all instructions. Not all of the products listed in Tables 1 and 2 are to be used on all stored grains. Be sure to apply the appropriate insecticide on the correct commodity and as they are intended as instructed on the label. Always wear personal protective equipment as the label instructs when mixing and applying insecticides. Safety is a critical component when using insecticides.

 

Table 1. Grain Protectants.

 

Table 2. Top-Dress Treatments.

 

Edmond L. Bonjour
Associate Extension Specialist – Stored Products Entomologist