Ahmad, Khawar Jawad (2002) FACTORS AFFECTING PEST HOST INTERACTION IN IPM OF HELICOVERPA ARMIGERA (HUBNER) IN PAKISTANspan>. PhD thesis, University of Agriculture, Faisalabad.
Studies were conducted to determine the factors affecting pest host interaction in IPM of Helicoverpa armigera (Hubner) in Pakistan in terms of food consumption and coefficient of utilization during the years 1998-2000 at Faisalabad (Punjab). Based on the data of food consumption and CU from preliminary screening trials, 13 plants (out of 44) viz., Calotrope, Winter cherry, Castor oil, Cattail, Horse purslane, Bermuda grass, Alfalfa, Maize, Okra, Rice, Rape seed, Sorghum and Tomato (showing comparatively susceptible, resistant and intermediate responses) plants along with two Cotton genotypes viz., NIAB-98 (late maturing) and CIM-446 (early maturing) were selected. Five plants were common and thus 15 selected plants in total were again offered as food to H. armigera to confirm the order of preference through their consumption and CO. Various morpho-physical and chemical plants factors viz., moisture content, hair density and length, thickness of leaf lamina. Total minerals, nitrogen, phosphorus, potassium, magnesium, ferrous, manganese, zinc, crude fiber, carbohydrate and fat contents in the leaves were correlated with the values of consumption and CU. Multivariate models were established among various combinations of plant factors and values of food consumption and CU to determine their contribution and to find out significant factors responsible for the express of resistant. The data were also subjected for Principal Component Analysis with the objective to find the role of various combinations of factors towards resistance. Various components of resistance like antixenosis and antibiosis were also studied in vitro. The summarized results are as follows- Studies revealed significant differences among selected 15 test plants regarding all the parameters. The selected plants in order of preference on the basis of consumption were Sorghum> Maize> Bermuda grass> Tomato> Cotton (NIAB- 98) > Alfalfa> Rice >Castor oil> Okra> Cattail> (cotton (CIM-446) -> Horse purslane> Rape seed>Winter cherry> Calotrope. The order of the preference on the basis of coefficient of utilization was Sorghum> Bermuda grass> Maize> Cotton (NIAB-98) > Tomato> Winter cherry> Castor oil> Alfalfa> Okra> Rice> Cotton (CIM-446) > Horse purslane> Calotrope > Rape seed> Cattail. None of the plants tested was found to be completely resistant to H armigera. The correlation between food consumption and coefficient of utilization was significantly positive. Moisture content showed positive while thickness of leaf lamina played negative role towards consumption and coefficient of utilization. Both these factors were significant. In multivariate regression models, moisture percentage alone contributed 50.8% role towards resistance in term of consumption and the same factor played 40.5% role towards resistance in terms of coefficient of utilization. With the addition of thickness of leaf lamina, which contributed negatively both for consumption and coefficient of utilization, the model played 63.2 and 53.2% role. The cumulative effect of all the morpho-physical plant factors was calculated to be 80.1 % for consumption while this effect was found to be 57.8% in term of coefficient of utilization. Principal component matrices in case of consumption revealed that moisture contents, length of hair on lower surface of leaves and thickness of leaf lamina were important showing 35.9% variance with all the other morpho-physical plant factors. Principal Component Analysis in case of CU, moisture content, length of hair on upper and lower surfaces and thickness of leaf lamina were important which contributed 38.20% variance. Ferrous and manganese contents showed significant correlation with negative and positive responses, respectively with consumption, whereas the effect of nitrogen and crude fiber contents was significant with positive and negative responses, respectively with the coefficient of utilization of the pest. Multivariate models revealed that moisture content, total minerals, nitrogen, potassium, calcium and magnesium contributed 19.5% role towards resistance in term of consumption and with the addition of ferrous, this value reached up to 33.7%. The addition of manganese, the coefficient of determination value was observed to be 53.0%. Similarly a model which comprised of total minerals, nitrogen, phosP40rus, potassium, calcium, magnesium, ferrous, manganese, zinc and fat contents showed 33.3% r91e towards the resistance in term of coefficient of utilization and with the addition of crude fiber this contribution reached up to 44.8%. Principal component matrices in case of consumption revealed that magnesium, phosphorus and ferrous were important. All these factors showed contrasting response with variance value of 32.10% Principal component matrices in case of CU revealed that magnesium, phosphorus and ferrous were the most important factors resulting variance value of29.80% There were the multiple factors, which contributed resistance to the pests rather than single factor. Antixenosis and antibiosis studies revealed that Sorghum, Tomato and Maize were important host plants which can be grown as alternate hosts to save the Cotton as well as other major cash crops from the ravages of this notorious pest. Maximum egg laying and emergence were observed on Castor oil followed by Maize Sorghum, Tomato and both genotypes of Cotton. Castor oil, Maize and Tomato also showed favorable host plants for the development of the pest.
|Item Type:||Thesis (PhD)|
|Uncontrolled Keywords:||Pest Host Interaction, Helicoverpa Armigera (HUBNER), Food Consumption, Coefficient Of Utilization, Calotrope, Winter Cherry, Castor Oil, Cattail, Horse Purslane, Bermuda Grass, Alfalfa, Maize, Okra, Rice, Rape seed, Sorghum and Tomaton, NIAB-98 (late maturing), CIM-446, Host Plant,|
|Subjects:||Agriculture & Veterinary Sciences(a) > Agriculture(a1)|
|Deposited By:||Mr Ghulam Murtaza|
|Deposited On:||23 Jun 2006|
|Last Modified:||04 Oct 2007 21:00|
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