临沂市覆膜西瓜田杂草的发生及防除李长存（山东临沂市植保站，２７６００３）西瓜是我市的主要经济作物之一。近几年，由于普遍推广地膜覆盖，覆膜后西瓜田杂草孳生快、密度高、为害重，且无法中耕、拔除，一般造成减产１５％～２０％，个别地块高达３０％以上。为此，笔... Occurrence and Control of Weeds in Film Watermelon Field in Linyi City LI Chang-cun (Plant Protection Station, Linyi City, Shandong Province 276003, China) Watermelon is one of the main cash crops in our city. In recent years, due to the widespread promotion of plastic film mulching, the watermelon weeds in the mulching area quickly grows with high density and heavy weight and can not be plowed or removed. Generally, the yield is reduced by 15% to 20% and the individual plots are as high as 30% or more. To this end, pen ...