Colletotrichum truncatum, grown on rice grain (3 to 4 weeks, 22°C to 24°C) produced a fungus-infested rice mixture of microsclerotia and conidia (spores) in a ratio of ~9:1, respectively. Greenhouse tests of...Colletotrichum truncatum, grown on rice grain (3 to 4 weeks, 22°C to 24°C) produced a fungus-infested rice mixture of microsclerotia and conidia (spores) in a ratio of ~9:1, respectively. Greenhouse tests of this formulation (0.4 to 50 mg finely-ground fungus-rice product) which applied pre-emergence to 5 cm2 of soil surface, caused 22% to 96% hemp sesbania plant mortality, after 14 days. Post-emergence treatment (fungus-rice aqueous formulation;2.4 × 105 microsclerotia ml-1, 30% unrefined corn oil and 0.2% Silwet L-77 surfactant) of weeds surviving the pre-emergence application, resulted in 93% mortality, after 14 days. Based on greenhouse results, field tests were undertaken: 1) pre-emergence treatment (fungus-rice formulation at 2.4 × 105 microsclerotia cm-2), 2) post-emergence (fungus-rice product in 30% unrefined corn oil, 0.2% Silwet) only treatment, applied 15 days after planting and 3) pre-emergence treatment followed by post-emergence treatment (fungus-rice product in 30% unrefined corn oil, 0.2% Silwet) applied 15 days after planting to surviving weeds. Control treatments were: 1) autoclaved rice product sans fungus, 2) unrefined corn oil (30% unrefined corn oil, 0.2% Silwet in water) and 3) untreated plants. Planting dates were: early season (April-May), early-mid season (June-July), late-mid season (July-August), and late season (September-October). Weed mortality was recorded at 15 days for the pre-plus post-treatment, and at 30 days after planting for the pre-emergence only and the post-treatment only. The early season, pre-emergence treatment caused 67% hemp sesbania mortality (3-yr average) within 15 days and the post-emergence treatment caused 91% mortality of the surviving weeds. In the late-mid-season, pre-emergence treatment caused minimal (<5%) mortality at 15 days, but mortality in the post-emergence treatment was >80%. Results suggest that seasonal environmental conditions are important in the efficacy of this C. truncatum-rice product formulation when applied pre- or post-emergence to this onerous weed.展开更多
华山松大小蠹(Dendroctonus armandi Tsai and Li)是中国特有种,是为害华山松的先锋型害虫,给秦巴山区森林生态造成了极大的破坏。由于其为害具有隐蔽性,发现时已造成华山松死亡。研究概述了现阶段华山松大小蠹的发生规律、入侵机制和...华山松大小蠹(Dendroctonus armandi Tsai and Li)是中国特有种,是为害华山松的先锋型害虫,给秦巴山区森林生态造成了极大的破坏。由于其为害具有隐蔽性,发现时已造成华山松死亡。研究概述了现阶段华山松大小蠹的发生规律、入侵机制和风险评估情况,并基于此对华山松大小蠹及大小蠹属的天敌昆虫进行了统计和预估分析,可为进一步开发和利用天敌昆虫提供参考依据。展开更多
文摘Colletotrichum truncatum, grown on rice grain (3 to 4 weeks, 22°C to 24°C) produced a fungus-infested rice mixture of microsclerotia and conidia (spores) in a ratio of ~9:1, respectively. Greenhouse tests of this formulation (0.4 to 50 mg finely-ground fungus-rice product) which applied pre-emergence to 5 cm2 of soil surface, caused 22% to 96% hemp sesbania plant mortality, after 14 days. Post-emergence treatment (fungus-rice aqueous formulation;2.4 × 105 microsclerotia ml-1, 30% unrefined corn oil and 0.2% Silwet L-77 surfactant) of weeds surviving the pre-emergence application, resulted in 93% mortality, after 14 days. Based on greenhouse results, field tests were undertaken: 1) pre-emergence treatment (fungus-rice formulation at 2.4 × 105 microsclerotia cm-2), 2) post-emergence (fungus-rice product in 30% unrefined corn oil, 0.2% Silwet) only treatment, applied 15 days after planting and 3) pre-emergence treatment followed by post-emergence treatment (fungus-rice product in 30% unrefined corn oil, 0.2% Silwet) applied 15 days after planting to surviving weeds. Control treatments were: 1) autoclaved rice product sans fungus, 2) unrefined corn oil (30% unrefined corn oil, 0.2% Silwet in water) and 3) untreated plants. Planting dates were: early season (April-May), early-mid season (June-July), late-mid season (July-August), and late season (September-October). Weed mortality was recorded at 15 days for the pre-plus post-treatment, and at 30 days after planting for the pre-emergence only and the post-treatment only. The early season, pre-emergence treatment caused 67% hemp sesbania mortality (3-yr average) within 15 days and the post-emergence treatment caused 91% mortality of the surviving weeds. In the late-mid-season, pre-emergence treatment caused minimal (<5%) mortality at 15 days, but mortality in the post-emergence treatment was >80%. Results suggest that seasonal environmental conditions are important in the efficacy of this C. truncatum-rice product formulation when applied pre- or post-emergence to this onerous weed.
文摘华山松大小蠹(Dendroctonus armandi Tsai and Li)是中国特有种,是为害华山松的先锋型害虫,给秦巴山区森林生态造成了极大的破坏。由于其为害具有隐蔽性,发现时已造成华山松死亡。研究概述了现阶段华山松大小蠹的发生规律、入侵机制和风险评估情况,并基于此对华山松大小蠹及大小蠹属的天敌昆虫进行了统计和预估分析,可为进一步开发和利用天敌昆虫提供参考依据。
