不同药剂对辣椒疫病防治效果及根际微生物种群的影响

Control efficacy of several fungicides on pepper phytophthora blight and effects on rhizosphere microorganism

  • 摘要: 【目的】研究不同药剂对辣椒疫霉菌的生长抑制作用以及对辣椒疫病的田间防效和对辣椒的增产作用,旨在筛选出可有效防控辣椒疫病并对辣椒根际土壤微生物群落结构影响较小或有益的防控药剂,为辣椒疫病防控提供指导。【方法】以辣椒疫霉菌Ph2为试验材料,采用菌丝生长抑制法对15种药剂进行初筛;以生长抑制率为100.00%的药剂为候选药剂,辣椒疫病高发田块为试验地,采用随机区组试验设计,以灌根法为主要施药方式,统计施药后不同时段辣椒疫病发病率、病情指数并计算防效;收获期测定不同药剂处理辣椒生长及产量指标,计算增产率;采集辣椒根际土壤,采用平板计数法测定土壤细菌、真菌和放线菌菌落数量,计算细菌/真菌比,探索不同药剂对辣椒根际土壤微生物种群的影响。【结果】对辣椒疫霉菌生长抑制率为100.00%的药剂有6种,分别为33.5%喹啉铜SC、80%烯酰吗啉WG、72%霜脲·锰锌WP、687.5 g/L氟菌·霜霉威SC、23.4%双炔酰菌胺SC和64%噁霜·锰锌WP;田间防效试验结果显示,第3次药后33 d防效最好的是氟菌·霜霉威(93.86%),其次为噁霜·锰锌(71.78%);各药剂处理对辣椒生长指标影响差异不显著(P>0.05);鲜椒推测产量最高的是噁霜·锰锌处理(22.74 t/ha),氟菌·霜霉威处理次之(21.29 t/ha),较CK分别增产29.52%和21.22%;各药剂处理下的细菌/真菌比表现为霜脲·锰锌>氟菌·霜霉威>噁霜·锰锌>喹啉铜>双炔酰菌胺>烯酰吗啉,以霜脲·锰锌处理最高,为13.85,极显著高于其他药剂处理(P<0.01)。【结论】氟菌·霜霉威和噁霜·锰锌对辣椒疫病有较好的防效且增产作用明显,对土壤细菌生物量影响较小,可作为辣椒疫病的防治药剂加以利用。

     

    Abstract: 【Objective】 In this paper, the effect of different fungicides on the growth inhibition of Phytophthora capsici, pepper phytophthora blight field control and the yield increasing effect on pepper were studied, to screen out the fungicides which could effectively control the local pepper phytophthora blight and had little or beneficial effects on the rhizosphere soil microbial community structure of pepper, and provide technical guidance for pepper phytophthora blight control.【Method】 P. capsici-Ph2 was used as the test material. Fifteen fungicides were screened by mycelial growth inhibition. The six pesticides with growth inhibition rate of 100% were selected as the candidate agents. The high incidence plots of pepper phytophthora blight were used as experimental plots. The random plot experiment was designed to test the incidence rate, disease index and the control effect of pepper phytophthorablight at different times after irrigating the pesticide. The growth and yield indexes of pepper treated with different fungicides were measured at harvest time, and the yield increasing rate was calculated. Meanwhile, the rhizosphere soil of pepper was collected, and the colony numbers of soil bacteria, fungi and actinomycetes were measured by plate counting method. Bacteria/fungi ratios were calculated to explore the effects of different fungicides on soil microbial populations in the rhizospheresoil of pepper.【Result】 There were six fungicides with 100% growth inhibition rate to P. capsici, which were 33.5% oxine copper SC, 80% dimethomorph WG, 72% cymoxanil·mancozeb WP, 687.5 g/L fluopicolide·propamocarb hydrochloride SC, 23.4% mandipropamid SC and 64% oxadixyl·mancozeb WP. The field control effect test showed that fluopicolide·propamocarb had the best control effect on the 33rd day after root irrigation(93.86%), followed by oxadixyl·mancozeb(71.80%). There was no significant difference in the growth indexes of pepper among different fungicides treatments (P>0.05). The yield of fresh pepper was speculated to be the highest treated by oxadixyl·mancozeb(22.74 t/ha), followed by fluopicolide·propamocarb hydrochloride(21.29 t/ha), and their yield increase rate were 29.52% and 21.22%, respectively compared with control. Bacterial to fungal ratioswere cymoxanil·mancozeb>fluopicolide·propamocarb>oxadixyl·mancozeb>oxine copper>mandipropamid>dimethomorph. Bacterial to fungal ratio of cymoxanil·mancozeb (13.85) was the highest, and was extremely significantly higher than others(P<0.01). 【Conclusion】 Oxadixyl·mancozeb and fluopicolide·propamocarb hydrochloride have good control effect on pepper phytophthora blight, and have significant effect on increasing production. They have little effects on soil bacterial biomass, and can be used as fungicide for pepper phytophthora blight control.

     

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