南瓜疫病菌侵染模拟及流行预测研究

南瓜疫病是由 Phytophthora.cap isici引起的一种土传病害 ,是黑龙江省南瓜生产上威胁最大的病害之一。论文主要从两个方面对南瓜疫病进行研究。 1)南瓜疫病菌侵染模拟 ;2 )田间南瓜疫病流行动态研究

Studies on infection simulation and epidemic forecasting of phytophthora capsici

Squash blight disease is a disease which is caused by P.capsici,and also one of the most destructive diseases in Heilongjiang Province.A systematic studies were carride out and determined at two different levels.One aspect was simulative infection of the pathogen,another was epidemiology forecasting of the disease. The results showed: 1.Under manual control,the studies analysised the influence of temperature,content of soil water and both of them on the incident of squash blight.The incident of squash blight increased with increasing temperature up to about 30℃,and then declined.Optimum temperature for infection was between 26℃ and 30℃.Successful infection required at least 40% content of soil water and more than 80% content of soil water,incident was 100%.A regression model using the incident as the dependent variable accurately described infection level as a function of temperature and content of soil water.The infection percentage model as follow:SQRT(I)=1 381-1 133×10 -1 ×DT-6 588×10 -2 ×SW+5 133×10 -3 ×DT×SW-9 232×10 -5 ×DT 2×SW+2 093×10 -3 +8 194×10 -5 ×SW 2 R=0 9089 F=146 64 ss=0 0268 In which I is incident DT is temperature SW is water contain in soil. 2 By systematic survey of squash blight caused by P.capsici in 1997～1999 The results showed that Logistic model was the best one for simulating the disease progress curve.Busing primary disease incidence and several climate factors predicting the model for apparent infection rate was developed as follows r=-28.01+2.14×T+0.496×RQ-0 210×RD-0 073×Ln-0.083×T 2+0 0036×T×RD 2-0 0005×T×RH 2+0 0013×T 2×RH-0 0168×RQ 2-0 057×RD×RQ+0 0069×RH 2 R=0^99772 F=1948 33 ss=0 0135 In which r is the apparent infection rate.T is dialy mean temperature.RH is relative humidity and RD is rain day.$$$$