Effect of cucumber varieties and some chemical pesticides on the population density of Bemisia tabaci

Abstract

The current study was conducted to evaluate the sensitivity of three varieties of water cucumber Syrian, Dutch, French and the effectiveness of three insecticides Joker, Harvest, Chase against the tobacco Bemisia tabaci   Meza Tabachi in Hawija area - Kirkuk governorate. In the fall from August to December 2020, and the results showed that the Syrian variety made the varieties resistant to Bemisa tabaci, as it reduced the insect population density to 32.40 adult insects/10 leaves and 28.75 nymphs / 16. cm² in. As for the French and Dutch cultivars 44.85, 44.38 adults / 10 leaves and 40.77 and 39.95 nymphs / 16 cm² respectively with insecticidal effect on the insect, the results showed that the joker was the best. More effective in reducing insect populations, where the average density was 32.6 insects/10 leaves and 33.39 nymphs/16 cm² compared with Shays and Harves, where the average population density was 41, 3 and 47.72. adult. /10 leaves and 36.39 and 39.69 nymph 6 cm². The lowest population density of insects was recorded in the Syrian cultivar treated with Joker pesticide, with an average of 24.54 insects/10 leaves and 27.26 16 cm nymphs. All pesticides showed better efficiency in reducing insects. One day of spraying, then its efficiency began to decline after the third and seventh days of spraying, while the lowest population density of nymphs was recorded after the seventh day of spraying with pesticides, and the lowest population density was 24.52 insects/10. Leaves and 9.81 nymphs/16 cm² after the second spray of pesticides compared to the previous period and the first spray with an average population density of 53.91, 33.45 adults/10 leaves and 48, 53 and 21.07 nymphs/16 cm² respectively. The Joker was marked by low adult population density after 1 and 3 days for each of the first sprays, so what is it? On average, after 1 and 3 days of spraying 3.21, 4.77, 2.76, 3.76 insects/10 leaves, respectively, and for spraying days of nymphs 8.66, 4.88 and 3.88 nymphs were counted. / 16 cm² each, respectively