Role of the Parasitic Mite, Pyemotes Tritici (La Greze-Fossat and Montane) (Acari: Pyemotidae), and Certain Weather Factors in the Natural Mortality Percentage of Diapause Larvae of Pink Boll Worm, Pectinophoragossypiella (Saunders) In Cotton Bolls a

Somaa, H.M.H.; El-Keblawy, M.S.M. and Hend S. El-Tahawe

Abstract

The experiments were carried out during the cotton seasons of 2017 and 2018 inSakha Agricultural Research Station, Kafr El-Sheikh Governorate to evaluate the parasitic mite, Pyemotes tritici (La Greze – Fossat and Montane)(Acari: Pyemotidae) role and certain weather factors on the natural mortality percentage of diapause larvae of pink bollworm, Pectinophoragossypiella (Saund.) in cotton bolls and infestation ratein the next year. The parasitic mites began in little numbers, after the numbers of parasitic mites to increased through the two seasons. In the first season the lowest mortality % (29.61%) was recorded on The 21Th of January at mean number of (19.75parasitic mites /50 cotton bolls ), but the highest mortality%(45.28%) was recorded on the 5 Th of February atmean number of (183.00 parasitic mites/ 50 cottonbolls) .In the second season ,the lowest and highest mortality% (31.97,80.36%)were recorded on the 7Th of January and 19Th of March at mean numbers of (48.75,204 parasitic mites/ 50 cotton bolls) ,respectively. The role of the parasitic mite, P. tritici on the natural mortality % of larvae diapause of PBW was recorded significant positive correlation (0.455* and 0.511*) in the two seasons 2017 and 2018, respectively. The effect of temperatures was recorded significant negative correlation (-0.526* and -0.477*) on the natural mortality percentage of diapause larvae of pink bollworm in the two seasons, respectively. On the other hand the effect of relative humidity recorded positive and insignificant correlation (-0.367 and -0.178) in the two seasons, respectively. Therefore the rainfall was recorded significant positively correlation (0.592* and 0.484*) during the two seasons, respectively. In the 2017 season, the lowest mortality%(29.61%) at means of (12.260C,72.99%R.H. and 1.2mm/day f rainfall).while the highest mortality% (45.28%) at means of (11.29OC,70.87%R.H. and 13.50mm/day of rainfall).and the 2018 season, the lowest and highest mortality% (31.97,80.36%)at means of (17.18,16.28oC;77.63,74.00%R.H. and 1.46,2.97mm/day of rainfall),respectively.

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