Reproductive performance of striped mealybug Ferrisia virgata Cockerell (Hemiptera: Pseudococcidae) on water-stressed cotton plants subjected to nitrogen fertilization

Abstract

Sap-sucking sessile insects depend on their selected host plant for their development; hence, they are influenced by the nutritional quality of the plant, especially the available nitrogen (N) and water content in the plants. The levels of N in the plant sap can vary as function of the N fertilization applied to enhance crop yield, while deficit of water takes place during drought periods. The performance of the striped mealybug on cotton plants subjected to N fertilization and water stress (=deficit of water) was evaluated. Potted cotton plants grown in a greenhouse were subjected to N fertilization and two irrigation regimes considering regular irrigation and water stress. Cotton plants were infested with 150 newly hatched nymphs. The survival was measured as the percentage of mealybugs alive 25 days after infestation. The biological traits of duration of development + the pre-reproductive period, and the number and sex ratio of the offspring were determined. The survival of nymphs was similar across all treatments and averaged 38 %. Likewise, the developmental times were similar across treatments averaging 47 days, with 84 % of female offspring. However, offspring production was nearly twofold higher for water-stressed plants with successive N fertilizations. Offspring production was increased by 37 % as a function of water stress, and by 18 % as a function of N fertilization. Therefore, we conclude that the striped mealybug performance is enhanced on cotton plants under N fertilization and water stress. Based on the results, proper fertilization and irrigation management relieving plant from stress can be helpful in avoiding generalized infestations of striped mealybug on cotton.