Pakistan Research Repository

Taxonomy, ecology and management of mealy bug on cotton in Pakistan

Abbas, Ghulam (2010) Taxonomy, ecology and management of mealy bug on cotton in Pakistan. PhD thesis, University of Agriculture, Faisalabad .

[img]HTML
19Kb

Abstract

A fairly exhaustive survey of morphological characters on the material from Pakistan, India and from several other sites in Asia, have revealed that the morphological variability of the species in Pakistan falls within that of Phenacoccus solenopsis Tinsley, and it is recommended that, until the DNA studies currently being undertaken in the United States are completed, the name P. solenopsis Tinsley(Sternorryncha: Pseudococcidae)should be used for this pest. It is an aerial pest and passes all of its life cycle on aerial parts of the host plats, on tender shoots, leaves, flower buds and even on stem. It has been noted to reproduce sexually. Its mode of reproduction is ovoviviparous ie. it retains the eggs in the body until they are ready to hatch. Number of crawlers is variable and depends upon source of food and environmental conditions. Its life cycle is variable with response to changing environmental conditions, availability of preferred host and its physical health. It is dimorphic insect having a winged male and wingless female. The crawlers can be identified for their sex with a very careful examination under microscope but after second instar the male can be identified with naked eye as the female moults into 3rd instar whereas, males transforms into prepupa. It is most active earlier instars and most of the dispersal occurs through initial instars. The number of eggs developing in one female is variable depending upon the type of the host plant.Newly emerged crawlers are capable of moving and feeding freely. The newly crawler are tiny (0.5 mm) and relatively transparent, therefore they can hardly be observed with an overview except a careful observation. In 1-2 days size is increased and wax is deposited on the body which increases its visibility. It has been recorded on 55 host plants in 18 families. In addition to cotton tract it has also been recorded in other districts.It has been observed in 20 districts of Punjab, 14 districts of Sindh, one district each from NWFP and Baluchistan, in 6 out of 10 agro ecological zones of Pakistan. These districts have been confirmed by the author, still there are some districts and localities which are prone to the occurrence of this pest. This pest can find a large number of alternate host plants in agro ecological conditions of Pakistan. A number of beneficial insects and spiders have been observed feeding on the pest but these are wiped out by the indiscriminate spraying process adopted to protect the crops. Relative resistance of the present 10 cotton cultivars shows that they are nearly equal in their response towards infestation of cotton mealy bug Psolenopsis none of them is resistant to this pest. The relative efficacy of the insecticides shows that the pesticides used fall in the following sequence after 72 hours of the application; Methidathion> Profenophos > Methomyl > Imidacloprid > Carbosulfon > Bifenthrin > Acetameprid > Fenpropathrin >Buprofezin > Control. Any how for safety to benificials the sequence was reverse ie., Control> buprofezin> Imidacloprid> Methomyl> Fenpropathrin > Bifenthrin> Acetameprid> Profenophos> Methidathion. The research trial for optimum quantity of spray volume showed that 100 & 120 liters water used in one acre (43560 sq ft) was the optimum volume,more than this was also good but less than this volume resulted in low control as there was no proper coverage of the spray material on the target pest and the pest escaped and resulted in build up of population again. Similarly,it was revealed that there is no additional effect of the additives like detergent, vegetable oil and mineral oil in the spray material, which were recommended as hit and trial from various agencies and persons, rather it affected the plant health so it should be avoided.

Item Type:Thesis (PhD)
Uncontrolled Keywords:Management, Exhaustive, Morphological, Species, Cotton, Examination, Districts, Additional, Bug, Ecology, Mealy, Overview, Taxonomy
Subjects:Agriculture & Veterinary Sciences(a) > Agriculture(a1)
ID Code:6947
Deposited By:Mr. Javed Memon
Deposited On:15 Aug 2011 09:35
Last Modified:15 Aug 2011 09:35

Repository Staff Only: item control page