储粮害虫防治的研究进展

储粮害虫的危害能够引起粮食减产和品质下降。介绍了国内外粮库储粮害虫防治和农户储粮害虫防治的研究进展,并阐述了所存在的不足,为从事储粮害虫防治的研究提供参考。     

九种药用植物提取液对储粮害虫毒杀作用的研究

本文介绍了中国的丹皮(Paeonia suffrutiposa Andr.)、蛇床子(Cnidiummonnieri(L.)Cuss.)、花椒(Zanthoxylum bungeanum Maxim.)、姜黄(Cur-cuma longa auct.non L.),木香薷(Elsholtozia stauntonii Benth)、苦楝(Me-lia azedarach L.)、槟榔(Areca Catechu L.)、半夏(Pinellia ternata Breit)和乌梅(Prunus mume Sieb.et Zucc.)等九种药用植物,采用点滴法、喷雾法、拌粮法和熏蒸法,对玉米象(Sitophilus Zeamais Motschulshy)、谷蠹(Rhizopertha domin-ica(Fabricius))、杂拟谷盗(Tribolium confnsum Jacqnelin du Val)、赤拟谷盗(Tribolium castanneum Herbst)和绿豆象(Callosobruchus chinensis(L.))等虫种,进行了室内毒力测定和毒杀作用的研究。结果表明,苦楝油、木香薷挥发油和丹皮乙醚热提取物均具有较明显的接触致死效应;蛇床子95%乙醇热提取物也具有一定的接触致死作用。其中木香薷挥发油还具有较强的熏杀作用。苦楝油拌粉处理赤拟谷盗各个虫态,导致形态畸形;丹皮粗提物对谷蠹和赤拟谷盗等成虫亦具有相似作用。槟榔—正丁醇提取物对杂拟谷盗幼虫中肠淀粉酶的活性具有一定的抑制作用。     

Effects of Combine Harvesting on Head Rice Yield and Chaff Content of Long and Short Grain Paddy Harvest in Sri Lanka

Paddy harvesting is the process of collecting the mature rice crop from the field which consists of activities such as cutting, handling, threshing and cleaning. Cutting, threshing and cleaning plays an important role to reduce postharvest losses. Lower performance of traditional harvesting process, labour shortage, reduced turn-around time and use of high yielding varieties have inevitably forced farmers to shift into mechanical grain harvesting in Sri Lanka. Rice milling is carried out to produce an edible polished or white rice product from harvested rough rice. Head rice yield is considered for marketing purposes because broken rice has low price in the market. Field survey was conducted in Polonnaruwa, Ampara and Hambanthota districts to identify most popular types of combine harvesters operating in the above districts. Paddy samples were collected from harvest of two most popular models of combine harvester in triplicate. Paddy sample of 1m² area from every paddy field were harvested separately by manual harvesting followed by manual threshing and cleaning in laboratory as control sample of relevant paddy field. Moisture content of the paddy grains were measured in the paddy field using digital moisture meter before harvesting. Paddy samples were subjected to sun drying until the moisture content come down to 14±1% before the quality analysis in the laboratory. Each paddy sample was analyzed for moisture content, chaff percentage and head rice yield percentage (HRY). Paddy was milled using laboratory scale rubber roll sheller and abrasive polisher. Chaff content percentage was measured by adding 100 ml of paddy to water and volume of chaff was measured using graduated cylinder. HRY was calculated dividing the weight of grain partials, which are larger than the ³/₄ of the grain, by weight of paddy sample. HRY between the two combine harvesting machine models evaluated were not significantly different at p<0.05 and also it was not significantly dependent on the harvesting methods such as combine harvesting and manual harvesting. The chaff content was significantly higher in model-2 in comparison to control sample for long grain paddy while model-1 was not significantly different with control sample for short grain paddy.