Studies On The Inhibitive Activity Of ZNQ-0317 Against Phytophthora Infestans And Its Mechanism

ZNQ-0317 is synthesized by China Agriculture University. In this research, the inhibitive range was determined, and the effect of ZNQ-0317 to mycelium growth, sporangium produce, the release of zoospores from sporangia and cystospore germination was determined. The mode of action and residual activity was determined on green house tests. The mechanism of action of ZNQ-0317 was simply discussed. The combinational action of ZNQ-0317 with metalaxyl, mancozeb, cymoxanil and propamocarb was researched. The results include:1. Most of pathogens had no active in the vivo test. But the toxicity was very high to the Phytophthora infestans, Pseudoperonospora cubensis, Rhizoctonia solani, and the EC50 was 1.38μg/mL,5.33μg/mL,4.44μg/mL,respectively.2. ZNQ-0317 exhibited significant preventative action, and the disease control is 96% when the concentration is 800 μg/mL. Although the absorbed action is poor, the residual activity is excellent. It was showed that, in the greenhouse test, the disease control is 61.28%, 77.81%, 84.57% when the concentration was225g/ai, 300g/ai, 450g/ai, respectively.3. It could intensively inhibit mycelium growth, sporangium production and cystospore germination of Phytophthora infestans and the EC50 was 0.0663 μg/mL, 0.047μg/mL, 0.55μg/mL, respectively. It was insufficient in inhibiting the release of zoospores from sporangia and the EC₅₀ was 9.78μg/mL. Microscopic observation showed that the branch was fewer and the space is longer, but the difference of hypha diameter was not distinct. From the invading process, it had a spot of germinated cystospore 24 hours post-inoculation and there was no sporangium 96 post-inoculation when the concentration was 100μg/mL.4. ZNQ-0317 was detected to influence on the permeability of the cell membrane of P. infestans on the high concentration, and the difference was not distinct on the low and middling concentration. ZNQ-0317 had no effect on protein and DNA biosynthesis.5. It was determined that ZNQ-0317 mixed with metalaxyl,mancozeb,cymoxanil and propamocarb. the results showed that it had increased activity when ZNQ-0317: mancozeb was 1:1,2:1, and ZNQ-0317: cymoxanil was 1:1,2:1,5:1,8:1. But it had negative activity when ZNQ-0317: metalaxyl or ZNQ-0317: propamocarb in the tested proportion.