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Title of Thesis

Integrated Management of Rice Leaf Folder, Cnaphalocrocis medinalis (Guenee),  (Pyralidae: Lepidoptera) in the Punjab Pakistan.

Author (s)
Muhammad Saghir
Institute/University/Department Details
University of Agriculture Faisalabad, Pakistan.
Session
2009
Subject
Agricultural Entomology.
Number of Pages
175
Keywords (Extracted from title, table of contents and abstract of thesis)
Genotypes, Super Basmati, Medinalis

Abstract

The studies were carried out on the integrated management of rice leaf folder, Cnaphalocrocis medinalis (Guenee(Lepidoptera: Pyralidae), in the Punjab, Pakistan from 2005 to 2007. The main objectives of the studies were to screen out the various genotypes of rice against the rice leaf folder in order not only to identify the primary and secondary metabolites in comparatively resistant genotypes responsible for resistance mechanism but also to find out the impact of abiotic factors, like relative humidity, temperature, rainfall etc. on the population fluctuations of rice leaf folder in addition to checking out of the efficacy of microbial and botanical insecticide against Cnaphalocrocis medinalis alone and in integration with an egg parasitoid Trichogramma chilonis for a successful control of the rice leaf folder. The data on post treatment increase in leaf-infestation and larval-population were recorded 10 days after the application of various treatments. The data on paddy-yield were, however, recorded at harvest. Cost benefit ratios were calculated, respectively, for each treatment, in order to evaluate their relative cost efficiency.
In the present project, sixteen advanced elite lines of coarse and fine rice including locally recommended varieties were screened for their high, intermediate resistance and susceptible responses based on the percentage of leaf-infestation, caused by Cnaphalocrocis medinalis (Guenee) during 2005. The data for larval-population, for each line/variety, were also recorded. Minimum leaf infestation was observed on Super Basmati (14.03 %), which was statistically at par with that of Basmati-370 (14.29 %) and Basmati-198 (15.29%) and differed significantly from genotypes PK-5261, 99515, Basmati 2000, KS-133, IRRI-6, KS-282, Basmati-385 and 4-1-7909 that had 17.03, 18.68, 18.97, 19.81, 20.93, 21.06, 21.62 and 21.91 % leaf-infestation caused by C. medinalis. Genotype 00518-2 was found to be comparatively susceptible with a maximum infestation of 31.80% and was statistically at par with genotypes 00515-1 having 30.79% infestation and was statistically different from genotypes 7429-5-14-1-1, 48463 and 99518-2 which had 26.71, 24.56 and 22.82% leaf infestation due to rice leaf folder. The maximum overall infestation of C. medinalis was observed in 2nd week of xiv September, 2005 and minimum observation was observed during the first week of this month.
From the results of preliminary screening trials, two genotypes, i.e., Super Basmati and Basmati-370 having least infestation and four genotypes (Basmati-2000, KS-133, IRRI-6 and KS-282) showing intermediate leaf infestation (18.97, 19.92, 20.92 and 21.06%) and two genotypes (00518-2 and 00515-1) having maximum leaf infestation (31.80 and 30.79% respectively), were selected for further screening during 2006 cropping season. Minimum leaf-infestation caused by C. medinalis was observed on Super Basmati (13.42 %), which was significantly different from that of Basmati-370, Basmati 2000, KS-133, IRRI-6 and KS-282 that showed intermediate response. Maximum leaf-infestation was observed on genotype 00518-2 and it was 30.84 %.
Overall results showed that the fine varieties of rice are comparatively resistant as compared to the coarse varieties. The genotypes selected from preliminary screening were also studied for their chemical-basis of their resistance to the rice leaf folder. The impact of abiotic factors such as relative humidity, temperature and rainfall etc. on the population fluctuations of aphids was also studied through the correlation and multivariate regression models. The results indicated that maximum temperature did not affect the infestation level significantly whereas the minimum temperature showed a significant and negative correlation with larval-population having r-values of -0.725 and -0.013 during 2005 and 2005-06 respectively. The relative humidity showed significant correlation having positive response with the larval-population of C. medinalis with r-values of 0.693, 0.865 and 0.574 during 2005, 2006 and 2005-06 collectively. The effect of rainfall on the larval-population of rice leaf folder was determined to be negatively significant with rvalues of -0.518, -0.906 and 0.705 during 2005, 2006 and 2005-06 cumulatively.
Genotypes 00515-1 contained maximum nitrogen and protein contents, which were calculated to be 2.63% and 16.41%, respectively. The result revealed that fine varieties contain minimum nitrogen contents, in their leaves, as compared to the coarse genotypes. The highest NDF, was recorded to be 67.33% in the leaves of KS-133, whereas the lowest NDF (51%)was found in Basmati 2000. The ADF contents in the xv leaves of KS-282, were found to be the lowest (21.67%), whereas the highest ADF amount was recorded to be 33% in the leaves of Super Basmati. Contents of non-reducing sugars, were comparatively higher in coarse varieties as compared with those of the fine basmati varieties, whereas the basmati varieties had more reducing sugar-contents in comparison to those of coarse grain varieties. Minimum cellulose-contents were present in leaves of IRRI-6 (19.33%), while maximum cellulosecontents were found in Basmati 370 (29.33%). The leaves of IRRI-6 possessed minimum Zinc quantity (0.2067 %), whereas maximum Zinc contents were found in Super Basmati (0.31ppm). concentrations of Calcium were comparatively higher in coarse grain varieties than those in fine grain basmati genotypes, while concentration of Potassium was more in the leaves of fine grain varieties as compared to those in coarse grain varieties. Maximum quantity of Phosphorus was calculated in genotypes 00518-2. Maximum Silica contents were found in genotype KS-282, which were calculated to be 3.38%.
Results of the experiment regarding the use of biopesticides for the management of rice leaf folder revealed a minimum increase in the infestation after the treatments with Bacillus thuringiensis followed by that with neem, spinosad, and darek which showed 6.09, 7.83 and 8.85% increase in infestation, respectively, seven days after the
application.

Studies regarding integration of various control tactics for the control of leafinfestation by rice leaf folder revealed that minimum increase in the infestation (0.59%) was observed in the treatment where integration of rope-dragging, Trichogramma sp., Bt and neem was carried out. The results of this treatment were statistically at par with those of T (Trichogramma + Bt + Neem), T8 (Trichogramma + neem) and of T7 (Trichogramma + Bt). The conclusion of these studies indicate that bio-insecticides (neem and Bt) affect the pest insect and they can be used in integration with egg parasitoid, Trichogramma to enhance its bio-efficacy against C. medinalis. Plant extracts and microbial formulations may be an effective alternative to conventional synthetic insecticides. The use of these biopesticides may play a more prominent role in integrated pest control programmes, in future.

 

 

 


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S. No. Chapter Title of the Chapters Page Size (KB)
  0    
1 1 Introduction 2
       
       
       
33 KB
       
       
 
2 2 Review of Literature 8
       
       


89 KB

       
       
3 3 Materials and Methods 21
46 KB

 

 

364 KB

 

57 KB

       
       
       
4 4 Results 31
       
       
5 5

Discussion

116
       
       
       
6 6 Summary 125

 

 

 

113 KB

 

 

137 KB

 

       
       
7  

Literature Cited

129
       
       
       
8   Appendices 149