Evaluation of some melon lines for their resistance against melon aphid, Aphis gossypii Glover

Abstract

The melon aphid, Aphis gossypii Glover (Hemiptera: Aphididae), which has a very wide host range including cucurbit species,causes serious direct and indirect damage to many crops. In both greenhouse and open field melon cultivation in Antalya (in southwesternTurkey), the control of this pest generally depends on the use of chemical insecticides, resulting in a rapid increase in resistance to a widerange of insecticides. In the present study, a total of 23 melon lines (22 indigenous and 1 exotic) belonging to 2 varieties (Cucumis melovar. inodorus and C. melo var. reticulatus) were evaluated for resistance to the pest. The study consisted of 2 consecutive work packages;in the first stage, 23 melon lines were evaluated for resistance to A. gossypii by using the antixenosis test method under growth chamberconditions at 26/20 °C (day/night temperatures, respectively), with a photoperiod of 16:8 h (light:dark); in the second stage, the mostresistant 4 lines (PI-414723, ÜNLÜ, TK15, and ŞÜKRÜBEY) were evaluated once more for resistance against the pest by using thechoice-test method in climate chambers at 26 °C and continuous light. N3, which was found to be the most susceptible line in the firststage of the study, served as the control. Counts were made 30 min, 1, 2, 4, and 8 h after the aphids were introduced into the test arena (a15-cm diameter Petri dish) including leaf discs (2.5 cm diameter) belonging to the 5 lines. The results of the choice test showed that theaphids preferred the PI-414723 line (2 aphids/disc after 8 h) less than the 3 other resistant lines. Additionally, aphids preferred to settleon the susceptible control (N3) (6 aphids/disc after 8 h) during the experiment. Overall, the results suggest that first PI-414723 and thenŞÜKRÜBEY, TK15, and ÜNLÜ may be used for the management of A. gossypii.