Insects gossypol toxicity

Another compound bordering between preformed and induced defenses is gossypol. This compound accumulates within epidermal glands on the surface of cotton plants and is very toxic to some insects [ .]. Gossypol, and a series of structurally related compounds on the same biosynthetic pathway, accumulate to substantially increased levels in plants that have been challenged by potential pathogens. For this reason they have been considered phytoalexins by some plant pathologists. Phytoalexins are inducible antibiotics and will be discussed later. 

Only a few efforts have been made to evaluate the effects of TA structural variations on toxicity. Methylation decreases toxicity of hemigossypol to Verticillium dahliae (25), of gossypol to rat mast cells (23), and of various TA to HelionTis sod. (22). In contrast, methylaTTon increases the toxicity of various TA"To nematodes (26) and the toxicity of heliocides to rat mast cells ( ). The order of toxicity of different TA to rat mast cells is quinones > heliocides > naphthols > binaphthols (23). Gossypol generally is somewhat more toxic to insects than heliocides, and quinones are least toxic (29,22). 

In addition to its adverse effects on maramals, gossypol has also been shown to be toxic to insects. Among the pesticides shown to manifest plant resistance are certain classes of phenolic compounds, including gossypol, flavonoids, and aromatic acids... 

The roles of these compounds are difficult to elucidate because compounds toxic to one insect may not be toxic to another, but glandless cottonseed is significantly more susceptible to insect attack than glanded cottonseed. Gossypol in cotton acts as an inhibitor of insects but the resistance has not been correlated with the total gossypol. Eagle (19) concluded... 

Gossypol, a polyphenolic binaphthylaldehyde that occurs in cottonseed, is toxic to animals, insects, and microorganisms. Ruminant animals can tolerate more gossypol in their diets than can nonrumi-... 

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