The Effect of Seasonal Temperature and Relative Humidity on the Infestation of Cotton Mealybug, Phenacoccus solenopsis Tinsley, on Tomato in Gezira State, Sudan (2016)

Abstract

Cotton mealybug, Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) is a serious pest of cotton, tomato, eggplant etc. The species is polyphagous and invasive and can attack many other economic crops. A field trial was carried out to study the effect of seasonal temperature and relative humidity on the mean number and infestation level of cotton mealybug on Tomato in Gezira State, Sudan. Tomato seedlings were transplanted into the field on 1st January and 1st August, 2016, respectively. Cultural practices were conducted as recommended by the ARC, Sudan. The infestation level and mean numbers of mealybug and were closely observed through weekly counts in both seasons. Temperature and relative humidity during the study period were provided by ARC, Meteorological Station. The results showed that the infestation level (50–90) and the mean number of cotton mealybug (0-15 insect/15cm) were lower on tomato in January where the temperature ranged between 20 ºc and 25ºc and the (RH) ranged between 30% and 40 %. The infestation level (80%) and the mean number of cotton mealybug (40–100 insects/15cm) were higher on tomato in March where the temperature ranged between 25ºc and 35ºc and the (RH) ranged between 20% and 30 %. The results showed that the infestation level (60–80) and the mean number of cotton mealybug (0-5 insect/15cm) were lower on tomato in August where the temperature ranged between 25 ºc and 30ºc and the (RH) ranged between 70% and 80 %.The infestation level (80-100%) and the mean number of cotton mealybug (40–60 insects/15cm) were higher on tomato in from September to November where the temperature ranged between 35ºc and 40ºc and the (RH) ranged between 40% and 60 %. It concluded that the seasonal temperature and relative humidity could influence the infestation of cotton mealybug on tomato crop.