Type Of Physiological Races Of Phytophthora Infestans In Potato And Control Of LB In Heilongjiang Province

The objective of this paper is to study the physiological races in Heilongjiang province, define situation on composing and distributing of physiological races, explore influence of meteorological factor to occur date and epidemic grade of Late blight , and study different control method of Late blight, in order to explore more effective measures to control method of Late blight.1. Through study on physiological races of potato Late blight with host, it have fifteen physiological races of potato Late blight in Heilongjiang province, including 0, 1, 2, 3, 4, 5, 7, 9, 11, 1.2, 2.3, 2.4, 3.4, 1.2.3.4, of which popular distributing of races are 0, 4 and 11.2. The key factor of effect on attack date of Late Blight is total rainfall between April and June. Rainfall more, occur date of Late blight earlier. According to regression equation(Y=31.66-0.18X) based on DPS, it can indicate that if rainfall increase 1mm, attack date of Late blight will ahead 0.18d. The important factors of influence epidemic grade of Late blight are total rainfall, average relative humidity in air and sunlight hour of between July and August. In the year of more rainfall, more average relative humidity in air, smaller of sunlight hour, epidemic grade of Late blight is serious. The key factor is rainfall.3.Through screening 275 resource material of potato, resistant materials in Heilongjiang province are 17, of which high resistance materials are 5, including ML-1, Zongxin24, 11085, kexin 12, middle resistant materials are 12, most parent material, including Bredor, Kexuan-3, ke97xuan 1122, Keyi, and so on.Using seed coating of potato can reduce effectively disease percentage of LB, but it hasn't effect on prevention and cure in the post of growth. The best prescription was "redomil +ABT +934 zengchanji" in all prescriptions. Compared with CK, the birth rate increase 36.43 %, rate of rot tuber reduce 87.89%, the yield increase 32.92 %.In all measures of prevent and cure LB, the best measure was pull out the haulm , controleffect got up upwards 90 %; the second was cut haulm , upwards 80 %; the third was chemical killing haulm, upwards 70 %; the last was spray fungicide ,upward 30 %. Considering net yield of tuber, pulling out haulm was the most effective measure of prevent and cure LB in varieties of susceptible and high susceptible of tuber, the second was cut haulm, but spray fungicide was the most effective method of prevent and cure LB on varieties of resistant tuber.Chemical and biological medicine testing result of Late blight showed that control rate of internal intake chemical agent (500 times ridomil) was 70.4%, the effect of exchanging application of ridomil and Lurutong was 47.40% ,the effect of 700 times Lurutong was 13.13%, biological agent such as fungicides(25.75%), mieshuangsu(400 times), the control effect were 63.19%.Chemical control effect was different in different variety, for example variety of Atlantic was 69.03%, but common control effect was 31.80%. Chemical control effect of variety of luyin 1 was 84.97 %, but common control effect was 59.21 %.