High Temperature Stress Decrease The Viability Of Four Kinds Insects On Cucumber Grown In Greenhouse

Based on the determination of mortality,hatchability and adult emergence rate of four kinds insects (whitefly, Red spider, Aphid and Leaf-miner) under high temperature condition in field and laboratory, to explore a more effective method for controlling of cucumber insects grown in greenhouse. The results showed that:1 The mortality of whitefly gradually increased with the increasement of temperature and the prolongation of time. The mortality of every instars reached more than 30% under 35℃in greenhouse. However, high temperature of 40℃was more significantly than 35℃and approximated the lethal temperature. There were only 10% of whitefly can survive under the high temperature of 40℃. Every instars unable to survive when the temperature reached up to 45℃or higher. Therefore, the optimal temperature should be maintained between 40-45℃, the treatment time should be for 3h.2 The mortality of aphid gradually increased with the increasement of temperature and the prolongation of time. All the instars of aphids were affected by the constant temperature of 35℃, mortality rate reached more than 60%. The lethal temperature almost approximate 40℃. There was only about 10% of aphid can survive under the high temperature. Every instars of aphids can not survive when the temperature above 45℃. Therefore, the optimal temperature should be maintained between 40-45℃and lasted for 3h.3 The mortality of leaf-miner gradually increased with the increasement of temperature and the prolongation of time. The percentage of moth emergence was less than 20%, but the mortality rate was only about 20% when the temperature maintained at 35℃. The mortality rate increased sharply under 40℃, there were less than 10% of adult and larvae can survive. Every instars of aphids unable to survive when the temperature reached higher than 45℃. Therefore, the optimal temperature should be maintained between 40-45℃, lasted for 3h.4 The mortality of red spider gradually increased with the increasement of temperature and the prolongation of time. Every instars of red spider were not affected by the temperature of 25℃, 30℃or 35℃and there were no significant diferences among them. The mortality rate was within 15%. The mortality rate was below 50% when the temperature reached up to 40℃and mortality rate was higher than 80% when the temperature reach up to 45℃. All the red spider died when the temperature reach up to 50℃. Therefore, the optimal temperature should be maintained between 45-50℃, the treatment time should be for 3h.5 The mortality of four kinds insects were consistent under laboratory high temperature condition except for the red spider. All the insects could be controlled at 40℃, and all died at 50℃. The high temperature of 40-45℃in greenhouse significantly affected all the insects. Therefore, the optimal temperature for the control of whitefly, Aphids and Leaf-miner should be maitained between 40-45℃. However, the heat tolerance of red spider is stronger than the other three insects, so the optimal temperature should be maintained between 45-50℃...