Study on Relationship between Occurrence of Lygus lucorum on Winter Jujube and Climate in North Shandong Province

The results of field investigation indicated that Lygus lucorum on winter jujube occurred for 5 generations every year in north Shandong province,the damage of the first generation was the most serious,and its harmful peak appeared in the last ten days of April and the first ten days of May.The overwintering eggs of Lygus lucorum were mainly laid on the residual stubbles cut from the braches of winter jujube,occupying 88.4% of the investigated eggs.Precipitation had enormous influence on the next year's population density of this insect pest,but had little implication on this year's.The drought could obviously decrease the population density in the next year.