Dhingra, M.R.Chouhan, Mahendra Singh2016-07-152016-07-152014http://krishikosh.egranth.ac.in/handle/1/68807Abstract Rice is a monocotyledonous cop, belongs to the Family Poaceae (Graminae) and genus Oryza. It has two cultivated & 22 wild species. Oryza sativa and Oryza glaberrima are the cultivated species of rice. Oryza sativa is globally cultivated species, while Oryza glaberrima is cultivated in West Africa. The crop is grown under different agro climate conditions and production systems. But, the most common practice is the transplanting method in puddled condition. It is an staple crop which is cultivated in diverse agro ecosystem in India and abroad. This crop occupies a key position in Indian Agriculture. About 60 to 65 % of the population at global & national level depends upon rice as a primary source of energy. Rice is cultivated mainly in Asian countries viz. India, China, Japan, Srilanka, Pakistan, Bangladesh etc. and more than 90 percent of the rice produce is consumed in these countries. The total area under the rice cultivation in the world is about 153.9 million ha, and the production is about 618 million tones. Amongst the rice producing countries, India occupies the first position with regard to the area (44.3 million ha), followed by China (29.3 million ha.). So far productivity is concerned, India occupies 15th rank in the World with a productivity of 3.01 tone/ha (FAO 2006). Since the India is far behind in term of productivity is comparison to many national and International level. Various factors has been attributed for low productivity in the country, But among them the cause of low productivity of the crop in our country are various. Biotic stress i.e. Insect pests, diseases and weeds, are the main constraint. Among the biotic stress, insect pests are major factors for low yield, More than 100 pests have been recorded on this crop, which attack the crop right from germination to harvesting. There are a dozen pests which are recognized as a key or major pest of rice. Among the infesting insects, there is a group of sucking pest which is cause havoc sometime in various region of the country. Brown plant hopper (Nilaparvata lugens, Stal.), White backed plant hopper (Sogatella frucifera, Horvath), Green leaf hoper (Nephotettix nigropictus, Stal.) and Gundhi bug (Leptocorisa varicornis Fabr.)] are the well known pests in different part of country as well as in Madhya Pradesh from the group. Rewa is situated in the north-eastern part of Madhya Pradesh at latitude 24º31' N, longitude 81º15' E and altitude of 306.06 m above the mean sea level. The region falls under subtropical climate with extreme winter and summers seasons. The agro climatic condition of Rewa is suitable for rice–wheat cultivation. The annual average rainfall varied from 1100 to 1200 mm. with humidity ranging between 71 to 89 % which is suitable more or less for the development all kind of rice pests, but most suitable for the sucking pests, who are the responsible for stunted growth to complete wilting or drying up of the crop besides as acting vector of disease like yellow mosaic & Tungro dieses etc. Gundhi bug (Leptocorisa varicornis Fabr.) is also one of them which is responsible for crop damage at vegetative and reproductive stage particularly at milky stage. It causes heavy losses from (68.7 to 98.7% with an average loss of 19.8%) in Madhya Pradesh. The severity of this pest has also been reported from Rewa district and need plant protection measures to save the crop, particularly by the ecofriendly approaches. The perusal of literature reveals that the studies so fare conducted for the management of this pests, shows the missing of important aspects like effect of sowing/planting time and varieties & evaluation of cultivar/variety at local level besides testing of new molecules Keeping these facts in view, the present study had been undertaken with the following objective. Objectives – 1. To identify the resistant genotype of rice against Gundhi bug. 2. To study the effect of planting dates on the incidence of Gundhi bug 3. To study the efficacy of new insecticides against Gundhi bug. Summary: Rice is an staple crop which is cultivated in diverse agro ecosystem in India and abroad. This crop occupies a key position in Indian Agriculture. About 60 to 65 % of the population at global & national level depends upon rice as a primary source of energy. It is cultivated mainly in Asian countries viz. India, China, Japan, Srilanka, Pakistan, Bangladesh etc. and more than 90 percent of the rice produce is consumed in these countries. The total area under the rice cultivation in the world is about 153.9 million ha, and the production is about 618 million tones. Amongst the rice producing countries, India occupies the first position with regard to the area (44.3 million ha), followed by China (29.3 million ha.). So far productivity is concerned, India occupies 15th rank in the World with a productivity of 3.01 tone/ha (FAO 2006). There are a dozen pests which are recognized as a key or major pest of rice. Among the infesting insects, there is a group of sucking pest which is cause havoc sometime in various region of the country. Brown plant hopper (Nilaparvata lugens, Stal.), White backed plant hopper (Sogatella frucifera, Horvath), Green leaf hoper (Nephotettix nigropictus, Stal.) and Gundhi bug (Leptocorisa varicornis Fabr.) are the well known pests in different part of country as well as in Madhya Pradesh and Rewa condition. It is one of the major insect pests responsible for poor yield of rice. Hence, to manage the pest, ecofriendly ; studies were conducted to find out the tolerant/resistant cultivar/varieties, of rice suitable time of planting for the Rewa condition and new safer molecules of insecticide. The finding of the objective based, studies has been summarized below- Screening of different paddy cultivar against Rice gundhi bug. Among the 55 screened cultivars CR 2711-76 was found least infested cultivar with 10% percent grain damage. There were 3 more cultivars i.e. Suraksha (12), CB-10-504 (12%) and CB-09-570 (15%). Which were categorized unde scale 5, 25 cultivars taken under scale -7 with damage ranging between 16-25 percent grain damage and the remaining 22 cultivars were categorized under scale 09 with percent damage more than 40 percent. Effect of planting dates on the incidence of Gundhi bug. Three date of planting i.e. early planting, normal planting and late planting were tried to find. The suitable planting time with less infestation of gundhi bug. It was found that planting time of crop had the influence on gundhi bug population. The bug infestation began 50 days after transplanting in all the treatment but variation in the infestation reflected after 60, 70, 80 and 90 days of transplanting. The higher number of bug population was noted in the late planted crop (30/08/2013) with a significant reduction in yield (14.46 q/ha) as compared to the normal and early planting crop. Efficacy of new insecticides against Gundhi bug. To find out the ecofriendly molecules of insecticides, this experiment was conducted with six insecticides. Two of them with two different doses i.e. Triazophos (@ 750, 1250 ml/ha) and Sulfoxaflor (@ 313, 375 ml/ha). All the tested molecules were found effective in the tested doses as compared to untreated check. The insecticides application brought down the population of gundhi bug to 66.65% after 3 days of application to 91.50% after 10 days of spraying. The Monocrotophos @1390 ml/ha proved superior over all tested insecticide with population reduction to the extent of 91.50% followed by Triazophos @ 750 ml/ha and Coragen @ 150 ml/ha proved least effective (66.65%) among insecticides but keeping in view their nature and mode of action it can be used in rice ecosystem for the IPM practice, which allow the some population to survive for the consumption of natural enemies. However, their time of application need further research. The order of field efficacy of tested insecticides at their normal and variable doses given below- Rynaxypyr(T6) < Sulfoxaflor(T4) < Triazophos(T1) < Buprofezin(T5) <Triazophos(T2) < Sulfoxaflor (T5) < Acephate(T7) < Monocrotophos(T8). The above insecticides showed their effectiveness at 3 & 10 days after treatment. The response of insecticide treatment also divulged in the form of high yield in the insecticide treated plot (36.36 q/ha) as compared to control (20.08 q/ha). Conclusion: From the above experimental findings, can be concluded that Cultivars i.e. CR 2711-76, Suraksha, CB-10-504 and CB-09-570 can be used as IPM tool for the control of gundhi bug, beside using them for breeding programme to develop gundhi bug resistant/tolerant variety for Rewa condition. The best time of planting, avoiding gundhi bug menace, is normal planting date i.e 13 August 2012. This date planted crop not only received less infestation but, also gave higher yield (36.46 q/ha). So, it can be considered the right time for rice planting. Among the tested molecules, though Monocrotophos proved best followed by Triazophos but, the importance of Rynaxypyr in the rice ecosystem cannot be neglected as it allow some population of the insect in the crop for the buildup of biotic stress. Which is important for Integrated Pest Management strategy & sustainable agriculture.enbugs, rice, insecticides, planting, crops, land resources, grain, yields, research methods, fruitsThesis