What are the causes of corn borer outbreaks?
What are the causes of corn borer outbreaks? Please explain. The causes of corn borer outbreaks are as follows: (1) Insect population base: the size of the insect population base from the previous generation is an important factor affecting the severity of corn borer damage. A large insect population base, under suitable environmental conditions, often causes severe damage. ...
What are the causes of corn borer outbreaks? Please explain.
The causes of corn borer outbreaks are as follows:
(1) Insect population base: the size of the insect population base from the previous generation is an important factor affecting the severity of corn borer damage. A large insect population base, under suitable environmental conditions, often causes severe damage.
(2) Temperature and humidity: the corn borer is suited to growth and development under high temperature and high humidity conditions. The suitable temperature for the growth and development of each instar is 16-30°C, with relative humidity above 60%. Corn borers mainly occur from June to September, when the temperature is suitable. Therefore, changes in the number of corn borers depend on humidity and rainfall.
(3) Corn varieties: damage varies greatly among different corn varieties. A borer-resistant substance called DIMBOA exists in corn tissues; when adults lay eggs on corn varieties with high DIMBOA content, the mortality rate of the hatched larvae is very high. In addition, due to differences in corn tissue morphology, adult egg-laying can be avoided and borer damage reduced; for example, if the hairs on the leaf surface and stalk are long and dense, borer damage is very light. Therefore, with different corn varieties, both the corn borer population size and the degree of corn damage differ.
(4) Natural enemies: there are many kinds of natural enemies of the corn borer, but the one with the greatest suppressive effect on the corn borer is Trichogramma. Trichogramma parasitizes corn borer eggs, so that the eggs cannot hatch normally, or the hatched larvae cannot grow normally, and it can play a certain role in reducing borer damage.
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