Insect pests nematodes

Others also have proposed that allelochemicals could prove useful in crcp protection, especially for minimizing the agricultural losses due to insects and nematodes, and for controlling diseases. The USDA Research Planning Conference in 1977 estimated that technological advances could reduce substantially the 30 billion in annual losses caused by pests and the cost of their control (37). This conference proposed the following strategies for research Tn allelopathy. 

Diazinon (phosphorothioic acid 0,0-diethyl 0-(6-mcthyl-2-(l-mcthylcthyl)-4-pyrimidinyl) ester) is an organophosphorus compound with an anticholinesterase mode of action. It is used extensively to control hies, lice, insect pests of ornamental plants and food crops, as well as nematodes and soil insects in lawns and croplands. Diazinon degrades rapidly in the environment, with half-time persistence usually less than 14 days. But under conditions of low temperature, low moisture, high alkalinity, and lack of suitable microbial degraders, diazinon may remain biologically active in soils for 6 months or longer. 

The use of nematodes as a biocontrol agent has been developed in the past 2 decades. Proper use of these bioagents on experimental scale has proved superbly successful in both short- and long-term pest suppressions. Crop insect pests are one... 

Steinemematid and Heterorhabditid nematodes attack a far wide spectrum of insects and are being exploited worldwide to manage crop insect pests. The host range of these nematodes varies with the species (Table 13.2) and it has been observed to... 

Ramos-Rodriguez O, Campbell JF, Ramaswamy SB. Efficacy of the entomopathogenic nematode Steinemema riobrave against the stored-product insect pests Tribolium castaneum and Plodia interpunctella. Bio Cont. 2007 40 15-21. 

Schmiege DC. The feasibility of using a neoaplectanid nematode for control of some forest insect pests. J Econ Entom. 1963,56 427 131. 

Morris, O.N. 1985. Susceptibility of 31 species of agricultural insect pests to the entomogeneous nematodes Steinernema feltiae and Heterorhabditis bacteriophora. Can. Entomol. 117, 401-407. 

Until twenty-five or thirty years ago, few laboratories around the world were seriously interested in these insect-eating nematodes and their bacteria, but agricultural and industrial scientists are now studying them enthusiastically. Mounting pressures to limit the use of synthetic chemical pesticides have had their effect, and the nematode-bacteria complex may offer a natural environmentally safe biopesticide. Both creatures are harmless to vertebrates, but the bacterial toxins are fatal to a wide spectrum of agricultural pests. An added advantage is that the nematodes actively seek out their hosts, something other pesticides cannot do. 

Pesticide. . any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any insects, rodents, nematodes, fungi, or weeds or any other form of life declared to be pests.. . . and any substance or mixture of substances intended for use as a plant regulator, defoliant or desiccant." Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA - 1947) DDT... 

The nematode species of most interest for the control of crop insect pests are from the genera Steinernema and Heterorhabditis, both characterised by their association with bacteria from the genera Xenorhabdus and Photorhabdus. These nematodes invade the insect and then release their symbiotic bacteria into the insect s haemocoel. The nematodes release metabolites that repress the immune system of the insect, allowing the bacteria to develop. The bacteria then release toxins that kill the insect within two to three days and also produce antibiotics that prevent the invasion of the dead insect by other bacteria. These bacteria then invade the entire insect cadaver and the nematodes subsequently begin to consume the bacteria. 

Pests include rats, a severe problem in some areas, wild animals, nematodes, and a number of insects. The most severe insect pests are the various types of borers, ie, the sugarcane borer, Diatrea saccharahs (F.) and the eldana borer, PLldana saccharina, which cause damage first by boring into the cane stalk, then by providing entry points for other diseases, and finally by reducing cane and juice quality. 

Weeds, insects, bacteria, nematodes, and fungi are major pests of crops and are estimated to reduce the global yield by 40% annually. 

Rotating to a cover crop also helps reduce insects and nematode pests, weeds, and plant disease. When a grower doesn t rotate, he is likely to be faced with one or more of these problems. Conventional growers can use pesticides to control these pests rather than rotate. So there is a choice between crop yield (while cover crops are planted) and pesticide use (that can maintain yield but may have toxic effects on the environment), at least in the short run. In the longer run, pests become resistant to pesticides and farmers may be forced to rotate because the crop can no longer be grown in that area. 

Steinernema feltiae A beneficial nematode that attacks the larvae of soil and aboveground insect pests such as fungus gnat, various flies, flea beetles, and some plant parasitic nematodes. 

Pest An insect, rodent, nematode, bacteria, virus, fungus, weed, and other organism that compete with humans for food or other resources. These are not beneficial but injurious to man and environment. 

Insects provide another difficulty. One of the axioms of entomology is that in the Northern Hemisphere, insect populations are larger and more varied in the eastern parts of a continental mass. In addition to its other problems, eastern viticulture must do constant battle against numerous voracious insect pests. The rose chafer regularly appears just in time to nip off inflorescences as they are about to flower. The Japanese beetle turns every leaf of a grapevine into a piece of lace, if allowed to. In the Tidewater sections of the lower part, nematode infestation can be so severe as to make viticulture almost impossible. 

Secondary Metabolites from Higher Plants as Pest Control Agents An activity related to various efforts to Identify compounds in plants with resistance to pests, and subsequently to attempt selection of lines with higher concentrations, is the utilization of these compounds (or the synthetic species) in field pest control. The following includes a few examples from a very large scientific activity. Jacobson (23) has tested azadlrachtin, a sesquiterpenoid from the neera tree, Azadlrachta indlca (A. Juss), against several insects and nematodes. It is effective at concentrations as low as... 

The natural ecosystem maintains a delicate balance between pests and predators. Pest insects can be controlled by the artificial release of predators. One example is a parasitic wasp, Diadegma insulare. The adult female wasp lays eggs in a Plutella xylostella larva and pupates inside the cocoon of the mature larva. This and other insect predators are available commercially, but the usage is limited. Protozoa and nematodes are also used in insect pest control. One example of a protozoan that effectively infects locusts and controls the population is Nosema locustae. A commercially available nematode insect control agent is Steinemema carpocapsae. This nematode parasitizes scarab larvae with a symbiotic Photorhabdus bacterium that produces insecticidal toxins. 

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