Insect Infestation on Bt. and Non-Bt. Cotton Cultivars

A field study was carried out to examine the resistance potential of promising cotton cultivars to insect pest infestation, during the year 2012. Five cotton varieties were examined for their resistance against insect pests including Hari Dost, Shahbaz-95, NIAB-78, Sindh-1 and Bt Cotton. The insect pests monitored in this study included thrips, jassid, whitefly and bollworms. The experimental process for monitoring the insect pests was initiated on 15th June 2012 and lasted on 12th October, 2012. The results showed that thrips population was significantly (P<0.01) lowest (6.28/plant) on Haridost, against 9.22/plant on NIAB-78, 13.79/plant on Bt cotton 14.89/plant on Sindh-1. while the highest thrips population (15.21/plant) was recorded on  Shahbaz-95. The peak thrips population was noted on 12th July observation on all three verities while on Bt cotton, the peak thrips population was recorded on 19th July. Bt Cotton. The peak activities of jassid was recorded in the month of August. Overall mean showed that the signifactly highest (P<0.01) population of jassid was recorded as (3.59/leaf) on Sindh1 followed by Bt cotton (2.81/leaf), Shahbaz (2.80/leaf), Niab -78 (2.19/leaf) and Hari dost (1.63/leaf). Similarly, whitefly was found active in month of July and Augest. Significantly, more population (P<0.01) was recorded on Sindh-1 (3.20/leaf) and minimum on Haridost (1.40/leaf). Bollworms infestation was significantly lowest (P<0.01), (2.04/plant) on Bt cotton against 2.56/plant on NIAB-78, 3.04/plant on Haridost, 3.22/plant on Sindh-1; while the highest bollworms population (3.36/plant) was observed on cotton variety Shahbaz-95. Bt cotton variety showed considerable resistance against bollworm complex, while NIAB-78 also showed some resistance against sucking. The infestation of sucking insect pests on haridost. Shahbaz and Sindh-1 as compared to Bt cotton. The infestation of thrips, and whitefly was  peaked in the month of July. While Jassid was found most active in August. Bollworms appeared in first week of July and remained active in the field in relatively higher population upto the mid of September and later decreased to negligible level. Keywords: Cultivar Resistance, Insect Infestatio

SEARCHING ABILITY AND FEEDING POTENTIAL OF LARVAE, 7-SPOTTED BEETLE COCCINELLA SEPTEMPUNCTATA LINN. UNDER LABORATORY AND FIELD CONDITIONS

ABSTRACT A field study was carried out to investigate the searching behaviour and feeding potential of 7-spotted beetle on mustard aphid was conducted at Department of Entomology, Sindh Agriculture University

Screening of Different Varieties of Okra (Abelmoschus esculentus L.) against Sucking Insect Pests

The screening of different varieties is one of the key strategies used in Integrated Pest Management to control the insect population and to escape the use of synthetic insecticides. This study was aimed to screen different okra varieties against sucking insect pest complex such as thrip, jassid, aphid, whitefly and mealybug. The experiment was conducted at Agriculture Research Institute Tandojam. The varieties such as Rama Krishna, Silky-460 and Bharat Kawairi were cultivated in RCBD layout and each treatment was replicated five times. The results revealed that the most infested variety was Bharat Kaiwari followed by Silky-460 and Rama Krishna throughout the experimental period. The highest mean population of the sucking insect pests (thrip, jassid, aphid, whitefly and mealybug) was 9.61±0.35, 3.22±0.13, 18.33±0.50, 3.25±0.15 and 3.75±0.19 respectively was observed on Bharat Kaiwari and the lowered on Rama Krishna. However, the attack of aphid was prominent on all okra varieties and overall pest attack was higher in the month of June. Similarly, the co-efficient correlation analysis showed a positive relationship of temperature and humidity (r= 0.012; r = 0.128) with thrip population whereas there was a negative relationship between temperature and humidity with remaining sucking pests. Both jassid and mealybug population indicated a significant difference with temperature. Similarly, relative humidity displayed a significant impact on population of mealybug (r = 0.365) and aphid (r = -0.096). Thus, it could be concluded based on the results that Rama Krishna is the most resistance against sucking insect pests as compared to Silky-460 and Bharat Kaiwairi