- #How are insects used as biocontrol agents cracked#
- #How are insects used as biocontrol agents free#
In corn, soybeans, and sorghum, the tolerances for insect infestation are different. Two insects of any kind in 1,000g of wheat, rye, or triticale cause the grain to be graded as U.S. In addition, the presence of insects in a grain sample can cause cash discounts for the grain. Insects also create fines and broken kernels when feeding that reduce air flow through grain and prevent proper aeration when fans are used. Insects damage grain by boring into the kernels and reducing grain quality through weight, nutritional, or quality loss spreading and encouraging mold germination adding to the fatty acid content of the grain and leaving quantities of uric acid that cause grain rancidity. Pest species vary in different parts of the U.S., although all stored grain insects are capable of decreasing grain quality. Other species such as the sawtoothed grain beetle, the red and confused flour beetles, the Indianmeal moth, and the larger black flour beetle feed on damaged grain or fines. Species such as the flat grain beetle, rusty grain beetle, and the foreign grain beetle feed primarily on mold.
#How are insects used as biocontrol agents cracked#
Other insect species do not develop within the kernels, although they may hide inside cracked grain, making detection very difficult. The maze weevil, rice weevil, granary weevil, lesser grain borer, and Angoumois moth all develop inside the kernels. The cycle is repeated when the female lays eggs inside the kernels. Some insects damage grain by developing inside kernels (egg, larvae, pupae), feeding on the inner endosperm, and producing holes in the kernel through which the adult insects exist. Also, grain can be inspected by screening or sieving and searching in the screenings for insects, examining kernels for damage, checking grain for webbing, and investigating off odors. Increasing numbers of insects indicate that management tactics need to be changed to prevent levels of infestation that damage the grain. The number of insects found in a trap should be recorded and charts constructed so that changes in population size can be easily noticed. Plastic pitfall traps should be checked for the species and numbers of insects, and grain temperatures should be monitored. Grain should be inspected every 21 days when grain temperature exceeds 60☏ (15☌). It is important to control insect population size before grain is irrevocably damaged by insect boring, feeding, and mold germination. Indeed, insect and mold metabolic activity can raise grain temperatures to 110☏ (43☌). In many instances, insect infestation amplifies mold problems in grain by exposing otherwise hidden endosperm surfaces to molds, transporting mold spores to new areas in the grain, and encouraging mold germination in microhabitats made moist by insect metabolic activity. The most favorable grain moisture range for stored grain insects is from 12 to 18 percent. In cold weather, insects congregate at the center and lower portions of the grain and may escape detection until high population numbers are reached. During the summer and fall, insect infestations are usually on the surface of the grain. Grain insects move within the grain mass at a rate that is determined by the and grain temperature.
#How are insects used as biocontrol agents free#
These areas must be kept free of insects to reduce migration to newly harvested grain. Insects can reach a high population size in unchecked grain bins, in subfloors or aeration ducts in bins, in equipment used to move grain, or in discarded refuse grain. Many grain insects are good fliers and move to newly stored grain from fields and from infested grain bins. High grain temperatures and moisture, along with dockage and broken kernels, provide conditions that accelerate mold and insect development. Stored grain is subject to insect infestation and deterioration from molds and bacteria. Reproduced with permission of authors from Stored Product Management, Chapter 13 Stored-product Insects and Biological Control Agents. Publication E-912, Oklahoma Cooperative Extension Service, Oklahoma State University, Stillwater, OK 74078 USDA ARS and the University of Wisconsin, Madison (retired) Department of Entomology, University of Minnesota
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