Viruses for insect control

HAMM Nuclear Polyhedrosis Viruses for Insect Control... 

There are also development efforts and first results to use the biological activity of bacteria and viruses for insect control directly, without the isolation of the active compound. 

Viruses belonging to the family Poxviridae cause disease in grasshoppers, forest lepidoptera, and turf beetles (As examples see ref. 7-9). However, because of their similarity to the pox viruses from vertebrates they were not considered good candidates for insect control until detailed study of the viral genome by restriction enzyme nucleotide fragment patterns demonstrated that they were quite different. There is no record of the entomopox viruses causing disease in vertebrates (10), Therefore it is likely that these viruses will become useful control agents in the future. 

Leaves yellow, curled, and wilted. Cause Aphids. Look for small, green, pink, gray, black, or white fluffy-coated, soft-bodied insects feeding on plants. Aphids can also transmit viruses. For mild infestations, knock pests off plants with a blast of water. Control with a weak insecticidal soap spray see the caution on page 213 before spraying. Prevent problems by using a foil mulch, which keeps aphids from finding plants. 

Prevention and Control Plant resistant cultivars. Mosaic viruses are mostly spread by insect pests, especially aphids and leafhoppers. If possible, deny these carriers access by covering your plants with floating row cover. For more control information on aphids and leafhoppers, see pages 269 and 302. respectively. Once plants are infected, there are no controls remove and destroy infected plants. 

Research work on the mode of action of these compounds furnished the theoretical basis for the chemical control of insects by means of chemosterilants, and most of the compounds showing such action were first described as antitumour agents. In no other field is the interaction between plant protection and human therapy so close as that between the chemotherapy of cancer and insect control by chemosterilants. The capacity of these substances to interfere with the biosynthesis of DNA served as the common theoretical basis. In addition to other effects such as antitumour and antimitotic effects, deactivation of viruses, etc., a characteristic outcome of this interference is the mutagenic effect and, closely related to this, inhibition of reproduction (Bofkovec, 1962). 

It scarcely need be mentioned that the presence of insects, diseases, and weeds can severely affect the returns to be expected from applications of nitrogen. Fortunately, insecticides, fungicides and herbicides for the control of most pests are available, but their use on many crops may be at prohibitive costs, and at much less than 100% efficiency of control. Nematode and virus diseases often are so difficult to control that a change in cropping system may be the most practical solution to the problem. A reduction of yield of only 10-15% may often eliminate most of the margin of profit. 

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