金山区稻麦轮作田水竹叶发生动态及药剂防治技术初探

Preliminary study on occurring dynamics of Murdannia triquetra and its controlling techniques with pesticide in rice-wheat rotating field in Jinshan district

2014—2015年,在上海市金山区对稻麦轮作田田间水竹叶生长动态及发生程度展开调查,发现该地区水竹叶发生频率为16.08%,面积发生率为15.70%,优势率为2.80%,且在直播稻田的发生程度重于机插稻田。田间药剂防效试验结果表明,当水竹叶2~3个分枝时,采用13%2甲4氯钠水剂、460 g/L 2甲·灭草松可溶液剂或200 g/L氯氟吡氧乙酸乳油可对其进行有效防除。对不同水竹叶发生程度的稻田进行穗粒结构分析结果显示,水竹叶发生程度在4级以上时,每667 m^2有效穗数明显降低;在3级以上时,随着发生程度增加,每穗总粒数、结实率和理论产量显著降低。

The occurrence, damage and distribution of Murdannia triquetra in rice-wheat rotation cropping fields were surveyed at Jinshan District, Shanghai in 2014-2015. Through the investigation, the occurrence frequency, area ratio and dominance ratio of Murdannia triquetra were calculated as 16.08%, 15.70% and 2.80% respectively, meanwhile the occurrence in direct seeding rice field were more serious than that in mechanical transplanted rice field. According to the result of field trial, 13% MCPA-Na AS, 460 g/L MCPA-Na·bentazone SL, as well as 200 g/L fluroxypyr EC could be uesd to control the occurrence of Murdannia triquetra effectively at the stage of 2-3 braches. The analysis of grain structure in different occurrences of the weed lays a foundation for tests of yield loss rate. When the occurrence degree of Murdannia triquetra was grade 4 or higher, effective panicle number per 667 m2 decreased significantly; when the occurrence degree was no less than grade 3, grain number per panicle, seed setting rate per panicle and theoretical yield per 667 m-2 were decreased significantly as occurrence degree growing.