The Mechanism Of The Formation Of Wings To Aphis Gossypii Glover And The Forecasting Model Of The Degree Of Occurrence

1,This study, mainly in the artificial climate box to study the impact of the degree of crowding, temperature, Photoperiod, each single factor and interaction, the mother-generation effect and the natural enemies on the Formation of Wings to cotton aphid, The main preliminary conclusions of the following.(1)In a constant temperature (27℃) and Photoperiod (L: D = 16:8),studied the impact of one instar nymphs in different degrees of crowding(1/dish, 10/dish, 20/dish, 40/dish and 80/dish) on the formation of wings to cotton aphid, the results show that: the greater of the degree of crowding of one instar nymphs, the more conducive to the formation of the individual wings. Five groups in the experiment, a density of 80/dish of the test forming the largest proportion of individuals, into a 19.1 percent winged rate, and in the 1/dish of the experiment, almost format wingless individuals.(2)In the same density (10/dish) and photoperiod (L: D = 16:8),studied the impact of different temperature (24℃, 27℃and 30℃) on the formation of wings to cotton aphid, the results show that: at low temperature more cotton aphid in favor of the formation of winged individuals. At 24℃, forming the largest proportion of individuals(9.3%), and with the 27℃and 30℃,had significant differences.(3)In the same density (10/dish) and temperature (24℃and 27℃),studied the impact of different photoperiod on the formation of Wings to cotton aphid, results showed that: at 24℃,the different photoperiod has significant differences to the impact on the formation of wings to cotton aphid, and short-day, more cotton aphid in favor of the formation of winged individuals; at 27℃, the different photoperiod had no significant differences to the impact on the formation of Wings to cotton aphid.(4) In the same density (10/dish), temperature (27℃) and photoperiod(long-day L:D = 16:8) conditions, studied crowding between the mother cotton aphid whether had the impact on the formation of wings to cotton aphid, results showed that: different degrees of crowding in adult aphid, the proportion of winged individuals of the generations has no significant difference.(5) In the same density (10/dish), temperature (27℃) and photoperiod(long-day L: D =16:8) conditions, studied the impact of Coccinella septempunctate when left over traces and stress in short distance on the formation of Wings to cotton aphid. The results showed that: compared with the control, the effect of natural enemies has significant differences to the impact on the formation of wings to cotton aphid.The stress of natural enemies in favor of the formation of winged individuals.(6) By designing a one-factor three-level and two-factors two-levels completely randomized experiment, study the impact of the temperature, photoperiod and crowding factors in different combinations on the formation of Wings to cotton aphid, results showed that: low-temperature, high-crowded and short-day combination in favor of the formation of winged individuals.2,In this research, we investigated the occurrence of the cotton aphid in the field in the Shihezi experiment station for two consecutive years(2007 and 2008), combined with meteorological data, we Preliminary analyse the population dynamic of alate preliminary, the preliminary conclusion as follows:(1)The occurrence of alate and nymph closely related with the total number of cotton aphid, the number of alate and nymph was consistent with the population dynamics of cotton aphid in cotton field. The peak time of the three are basically the same.(2)Analyse the climatic factors in 2008 with the dynamics of alate, indicating that: the daily average temperature and daily highest temperature have a certain influence on the the population dynamics of alate. Sustained high temperature can inhibit the growth of alate's population.(3)Study found that predator factors were consistent with the population dynamics of alate in cotton field. At the same time,we analyse the date of the occurrence of the second peak season of alate,the result is significantly related.(4)The occurrence of alate a related with the climatic factors, Sustained high temperature,raining or more rainfall at one time all can seriously inhibit the growth of alate's population.3,According to the historical data derived from Shihezi area in Xinjiang from 1990 to 2005 and 2007, the relationship between meteorological factors and the occurrence degree of Aphis gossypii Glover were analyzed by means of stepwise discrimination analysis. The result showed that the occurrence degree of Aphis gossypii Glover had closely relation to highest temperature between 21th to 25th of June, lowest temperature between 1th to 5th of July, lowest temperature between 11th to 15th of July, lowest temperature between 16th to 20th of July and rain capacity between 11th to 20th of July. Apply the selected factors with Fisher linear discriminant analysis in SPSS.A forecast model for Aphis gossypii Glover in Shihezi area was set up, as follows:Y1=-6.295X₁₆+19.764X₂₈+43.947X₃₀+48.857X₃₁-0.336X₃₃-1018.715 Y2=-3.403X₁₆+18.424X₂₈+36.918X₃₀+43.213X₃₁ -0.261X₃₃-844.391 Y3=-3.573X₁₆+19.274X₂₈+37.343X₃₀+44.656X₃₁ -0.274X₃₃-887.299 Y4=-2.274X₁₆+19.731X₂₈+35.862X₃₀+43.837X₃₁ -0.262X₃₃-898.875 Y5=-4.476X₁₆+18.219X₂₈+36.960X₃₀+42.846X₃₁ -0.285X₃₃-799.190Which, X₁₆ means the highest temperature between 21th to 25th of June,X₂₈ means the lowest temperature between 1th to 5th of July,X₃₀ means the lowest temperature between 11th to 15th of July,X₃₁ means the lowest temperature between 16th to 20th of July,X₃₃ means the rain capacity between 11th to 20th of July.Use above mathematical model validates the data in return, the percentage of the forecast corresponding to historical data was 93.3 %, and that accuracy of 2003 and 2004 forecast was right.