بررسی مقدماتی آفات (حشرات) هندوانه در گنبد و مینودشت

Considering wide spread of area under watermelon cultivation in the east of Golestan province, and since it is the only profitable crop in rotation with cereals in rain-fed fields. Preliminary study of watermelon pests and their enemies was carried out. From each sub-area some fields were chosen and within each field 10 plants were selected weekly for insects sampling. Then the numbers of harmful insects were counted and noted. Based on order and family characters, collected specimens were separated in the laboratory and then identified based on genus and species characters. Some specimens were sent to research institutes or scientific centers for confinnation. Based on the number of collected pests, relative frequency of the pests were determined on the basis of percentage. Some watermelon fields were chosen for collection of useful insects. In these fields specific areas were chosen for sampling. In these areas no insecticides were used in order to let pest and their natural enemies remain active naturally. In addition to the mentioned fields, useful insects were collected from other inspected fields and then were determined. During 2 years (1999-2000) over 30 harmful insects were collected from watermelon fields. The collected specimens belonged to the order of Coleoptera, Hemiptera ,Homoptera, Thysnoptera, Diptera and Hymenoptera. Among mentioned orders, Homoptera and Thysanoptera had the highest frequency and were important. As a whole during 1999-2000 cotton aphid,Aphis gossypii, had the highest frequency and was the dominant species. The cotton whitefly(Bemisia rabaci), Thrips tabaci and Empoasca sp were the other watermelon major pests. Also over 20 predator insects were collected. The conected specimens belonged to the order of Coleoptera, Hemiptera, Neuroptera and Diptera. Among the collected predators ,Coccinella undecempunctata L. had the highest frequency and was the dominant predator. Adonia decempunctata L., Chrysopa sp and Exochomus nigromacu/atus Goeze were the other watermelon major predators. Key words: watermelon, pests, natural enemies, Gonbad and Minodasht, Golestan

Keywords:

آفت هندوانه , گنبد , مینودشت , فون حشرات , دشمنان طبیعی , شرق استان گلستان , بالپوشان , ناجوربالان , حشرات شکارگر , کفش دوزک نقابدار , شته ‭Aphis spiraecola , ‬‭bemisis tabaci , ‬‭thrips tabaci , ‬‭empoasca sp , ‬بالتوری سبز