The Occurrence And Dynamics Of Main Pests Of Cotton In Tajikistan

1. Insect pest of cotton in Tajikistan mainly caused by Aphis gossypii Glover, Tetranychus turkestani, Helicoverpa armigera and Bemisia tabaci; Tajikistan pest occurrence degree can be ordered from heavy to light as Central capital part > Northern Sogd state > Southern Khanlon stateviewed from the pests occurrence area ratio. Over all, the pest occurence in Tajikistan is on a stable declined trend, which is related to the promotion and implementation of the pest biological control strategy in Tajikistan.2. A total of 17428 insect specimens, which totally belong to 7 orders, 28 families and 61 species, were collected under the light from 2014 to 2015 in Tajikistan. The species and quantity of southern cotton planting area(Kurgan-Tube region, Qubadiynscogo region) were significantly higher than those of central capital grain mixed zone(Institute of Zoology and Parasitology, Gissarscogo region); The species evenness of cotton planting area is also higher than that of the grain mixed zone, and in the insect community of cotton planting area, parasitoids such as Ichneumonidae, predative natural enemy such as Reduviidae remain have a certain number of population.3. The single day maximum trapping number of H.armigera at two sample plots of Southern Khanlon state respectively is 12(Kurgan-Tube region) and 13(Qubadiynscogo region) head, significantly more than 4 head daily maximum of the two sample plots in central districts(Institute of Zoology and Parasitology and Gissarscogo region). The population dynamics of cotton boll worm which using DYMAX model were highly consistent with the actual monitoring data.4. The Agrotis segetum of Tajikistan occurs 3-4 generations per year, the biggest trapping amount per day is 90 head single lamp. Agrotis segetum has a significant number advantage compared with other types of insects. The peak spacing between different generations is obscure due to the overlapping generationphenomenon in Tajikistan.5. The result of the influence of low temperature process on the mating and reproduction of H.armigera experiment showed that: there was no significant difference of the oviposition amount under five temperature treatment; 25?day/16?night treatment have the highest hatching rate while 25?day/7?night treatment have the lowest hatching rate, the hatching rate of 25?day/16?night and 25?day/13?nightconstant temperature treatment showed a significant difference with constant temperature of 25?constant temperaturetreatment, 25?day/10?night treatment and 25?day/7?night treatment; The longevity of 25?day/10?night treatment' s H.armigera adult was longest under five temperature treatments, while the shortest longivity exists in 25 ? constant temperature treatment; Adult longevity have a extension trend with the decreasing temperature; The spawning peak of 25?constant temperatureand 25?day/16?night treatment appeared at the second day after spawning, and the egg amount reached respectively 33.22 and 30.82; The spawning peak of 25?day/13?night treatment appeared at the fifth day after spawning, egg amount reached 26.27; The spawning peak of 25?day/10?night and 25?day/7?night treatment appeared at the sixth day after spawning, the egg amount reached respectively 27.93 and 21.96. The results showed that the decrease of temperature in a certain range could significantly prolong the longivity of H.armigera, but it would delay the mating and reproductive behavior and reduce the probability of effective mating.