Investigation on Outbreak of Sesamia inferens and Smut in Cane-growing Regions of Yunnan Province

[Objectives]This study was conducted to clarify the outbreak and disaster characteristics of Sesamia inferens Walker and smut in cane-growing regions in the low-latitude plateau of Yunnan Province,where there is continuous high temperature and drought in spring and summer.[Methods]A systematic investigation and analysis was conducted on different varieties in different types of fields in 16 cane-growing regions with outbreak of S.inferens and smut in Yunnan from 2019 to 2021.[Results]The outbreak of S.inferens and smut in cane-growing regions in the low-latitude plateau of Yunnan Province resulted in an average percent of dry hearts in the range of 17.3%-56.3%,and as high as 84.0%in severe cases.70%thiamethoxam seed treatment dispersible powder and clothianidin or thiamethoxam fertilizer granules were ineffective against S.inferens,while 10%monosultap·thiamethoxam or 10%clothianidin·monosultap granules had a significant control efficacy on S.inferens.The average diseased plant rate ranged from 14.8%to 89.7%in susceptible varieties with smut,and was as high as 100%in severe cases.ROC 1,Yuetang 93-159,Yuetang 00-236,and Liucheng 05-136 had strong resistance,with an average diseased plant rate of 0-5.5%and the highest rate of 7.6%.S.inferens and smut both broke out in cane-growing regions with an altitude below 1200 m.It is recommended to pay attention to disease and pest monitoring in cane-growing regions with an altitude below 1200 m,and combine it with the management of new plants and ratoon plants to effectively prevent and control the first and second generation of S.inferens-infested seedlings from March to May.It is also recommended to strengthen the promotion and application of excellent disease-resistant varieties,so as to achieve a reasonable distribution of varieties and fundamentally control the outbreak and epidemic of sugarcane smut.[Conclusions]This study provides a basis for the effective prevention and control of catastrophic S.inferens and smut caused by extreme climate.

Efficacy of High-efficiency Formula Pesticides for Controlling Sesamia inferens Walker and Ceratovacuna lanigera Zehntner

[Objectives]This study was conducted to screen high-efficiency formula pesticides and precise and efficient application techniques for the prevention and control of Sesamia inferens Walker and Ceratovacuna lanigera Zehntner.[Methods]Field efficacy trials were conducted using different combinations of 70%directed enhanced thiamethoxam seed treatment dispersible powder and 46%monosultap·Bacillus thuringiensis wettable powder.[Results]70%directed enhanced thiamethoxam ZF 450 g/hm^(2)+46%monosultap·B.thuringiensis WP 2250 g/hm^(2)had good control effects on both S.inferens and C.lanigera,so it was an ideal high-efficiency formula pesticide for controlling sugarcane S.inferens and C.lanigera.From January to May,combining with new plant or perennial root cultivation management,70%directed enhanced thiamethoxam ZF 450 g/hm^(2)can be evenly spread on sugarcane ditches and sugarcane stumps after being well mixed with fertilizers applied per hectare,and covered with soil in a timely manner,and during the peak incubation period of the first and second generation of S.inferens eggs from March to May,46%monosultap·B.thuringiensis WP 2250 g/hm^(2)was sprayed to the leaf surface in the mixture with water 675 kg with an electric backpack or a motorized sprayer.In such a way,the control efficacy on dead heart seedlings could reach over 89.8%,and that on C.lanigera could reach 100%.Meanwhile,it could effectively and concurrently control thrips,and the increases in yield and sugar content could reach 29310 kg/hm^(2)and 5.9 percentage points,respectively.[Conclusions]The promotion and application of the formula pesticide could achieve precise application and control of sugarcane pests,and improvement of sugarcane quality and planting efficiency,and help promote green prevention and control of sugarcane diseases and pests and the sustained high-quality development of the sugar industry.

Lethal and Sub-Lethal Effects of Transgenic Rice Containing cry1Ac and CpTI Genes on the Pink Stem Borer, Sesamia inferens(Walker)

Lethal and sub-lethal effects of transgenic rice containing cry1Ac and CpTI genes on the pink stem borer, Sesamia inferens, were studied to collect information for ecological risk assessment on insect-resistance of transgenic rice. In vitro insect-feeding bioassays were conducted to evaluate the lethal and sub-lethal effects of transgenic rice lines （II YouKF6 and KF6） containing cry1Ac＋CpTI genes on S. inferens at four different growth stages, viz., seedling, tillering and elongation, booting, and milk and maturing. Transgenic rice at seedling stage showed significantly high lethal effect on S. inferens with the shortest lethal duration for 50 and 100% individuals and the highest corrected mortalities after feeding on transgenic lines at this stage for 3 and 6 d. Followed by tillering and elongation stage, 50 and 100% S. inferens were dead after feeding on transgenic lines at this stage for 4 and 10 d, respectively. Moreover, corrected mortalities for 6 d feeding on transgenic lines at this stage were significantly higher than that at booting, and milk and maturing stages. Lethal effect of KF6 on S. inferens decreased significantly at booting stage. Lethal duration for 50% S. inferens significantly extended and its corrected mortalities for 6 d feeding also declined remarkably. However, lethal effect of II YouKF6 on S. inferens did not decrease significantly at this stage. Transgenic rice at booting, and milk and maturing stages did not show significant lethal effect to S. inferens and it showed the longest lethal duration for 50% individuals and the lowest corrected mortalities for 3 and 6 d feeding. A few larvae of S. inferens could survive, pupate and emerge on these two transgenic lines at booting, and milk and maturing stages. Sub-lethal effect of two transgenic lines on S. inferens also differed significantly between different developmental stages. Continuously feeding on transgenic rice lines at seedling, and tillering and elongation stages delayed the development of larvae and pupae and decreased pupation rate, but no effect was observed on eclosion rate. Larval development was significantly inhibited after feeding on transgenic rice at booting stage, but no obvious effect was observed in pupal stage, pupation and eclosion rate. There were no significant differences for larval and pupal development, pupation, and eclosion rates between feeding on transgenic and control rice lines at milk and maturing stage. Larval and pupal weights significantly declined, but no influence was observed on fecundity when S. inferens infested on transgenic rice at any stage. These showed that there were significant differences in lethal and sub-lethal effects of transgenic rice on S. inferens among developmental stages, and the effects gradually decreased with the increase of growth stages of rice plant.

川西水稻螟虫组成及发生危害新特点(英文)

[ Objective ] The paper was to study the composition of rice stem borers in western Sichuan Province and the characteristics of their occurrence and dam- age. [ Method ] Rice stem borers in western rice areas in Sichuan Province were composed of Chilo suppressalis, Tryporyza itwertulas and Sesamla inferens. C. sup- pressalis was the dominant population in most rice areas in western flee areas in Sichuan Province. T. incertulas had distribution and damage in Longquan, Qingbai- jiang and some rice areas, showing increasing trend of spread. The population of S. inferens was the minimum, but it caused serious damage in late period of rice. [ Conclusion] The result provided theoretical basis for proposing effective control measures against rice stem borers in western rice areas in Sichuan Province.