白兰瓜疫病侵染循环、流行因素及防治研究

德雷疫霉(Phytophthora drechslcri)游动孢子接于白兰瓜(honey dew)叶片上,12小时侵入率达19.3%,96小时孢子囊形成数254.3个/cm~2;德雷疫霉 A_1型与辣椒疫霉(Phytoph-thora capsici)A_2型配对,接于白兰瓜叶上形成大量卵孢子。连续降雨和高温,或高温天气给瓜田灌水是疫病流行的决定因素。70%代森锰锌在低浓度时对德雷疫霉、辣椒疫霉菌丝生长、孢子囊和卵孢子形成均有明显的抑制作用。高畦栽培对烂秧防效达89.2%—92.0%,对烂瓜防效达100%。

STUDY ON INFECTION CYCLE,EPIDEMIC FACTORS AND THE CONTROL OF PHYTOPHTHORA BLIGHT OF HONEY DEW

Penetration rate was 19.3% on 12 hours after inoculation with mo-tile zoospores on leaves of honey dew.Sporangia number formed was254.3/cm~2 on 96 hours after inoculation with motile zoospores on leavesof honey dew.Compatible mating cultures of strains of Phytophthoradrechsleri A_1 and P.capsici A_2 produced oospores abundantly on leavesof honey dew.The epiphytotic was favored by high temperature and rainfall.Toomuch irrigation in not weather also affected epidemics of the diseases.70% mancozed at low concentrations highly inhibited myceliumgrowth and formation of sporanga and oospores of Phytophthora drechs-leri and P.capsici.Using high ridge cultivation,the control effect was89.7%-92% for young plants and 100% for fruits.