MANAGEMENT OF MAJOR LEPIDOPTERAN INSECT PESTS OF RICE
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Date
2021
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Birsa Agricultural University, Ranchi
Abstract
Rice (Oryza sativa L.) is one of the most vital components of daily diet. Among the various insect pests causing economic loss to rice crop, lepidopteran group of insect pests especially yellow stem borer, leaf folder and caseworm could be considered as regular and major insect pests of economic significance. In order to explore information pertaining to multifaceted management tools used against these major pests, the current thesis protocol entitled “Management of major lepidopteran insect pests of rice” has been undertaken with five major objectives.
Five field experiments were conducted during Kharif, 2019 and 2020 to meet the requirements of five set objectives of the thesis protocol. Among the various weather factors, the maximum atmospheric temperature had significantly positive correlation with DH and significantly negative correlation with WEH caused by YSB. Sunshine hours had significant and negative impact on the incidence of caseworm whereas number of rainy days had significant and positive impact on the incidence of caseworm. Almost all the weather factors had non-significant impact in regulation of incidence of leaf folder.
The earlier was the dates of transplanting lesser was the incidence YSB and leaf folder which in turn, realized higher yield of grains of rice and delaying the date of transplanting was responsible for more incidence of YSB and leaf folder realized lesser yield of rice. Accordingly, earlier planted (1st July) rice, var. Naveen realized the highest grains yield (46.76 q/ ha) followed by normal planted (20th July) crop and late planted (8th August) crop realizing 43.64 q/ ha and 36.13 q/ ha, respectively.
Among the 16 tested rice varieties, Lalat, Naveen, CR-Dhan 201, CR Dhan 303, CR Dhan 304 and Suraksha emerged as resistant and promising against yellow stem borer receiving DH and WEH below 10 per cent while CR Dhan 304, Suraksha, CR Dhan 201 and PAC 801 emerged as resistant and promising against leaf folder. The hybrid rice variety US-380 received moderate level of incidence of YSB and leaf folder but realized the highest grain’s yield (65.97 q/ ha) and hence US-380 could be rated as tolerant to YSB and leaf folder.
On comparing the performance of BIPM (bio-intensive pest management) and F. P. (Farmer’s practice) operations it was encouraging to mention here that BIPM-operation is eco-friendly in nature resulting in the higher population of the predatory fauna viz. spiders, coccinellids and mirid bugs as compared to that of F.P. practices. The results of comparative studies of BIPM and F.P. operations revealed that the intensity of incidence of major lepidopteran pests viz. YSB and leaf folder recorded in BIPM and F.P. operations remained statistically at par resulting in realization of grains yield of 35.75 and 38.50 q/ha, respectively, which were statistically at par to each other.
Price of organic rice is much more higher as compared to that rice grains produced through the conventional method (i.e. F.P.) of cultivation. Therefore, BIPM module could be able to realize much higher net monetary benefit (Rs. 1,99,371/ ha) as compared to F.P. module which give rise to the net benefit of Rs. 88,841/ ha. As such,
the benefit cost ratio of 5.42:1 realized through BIPM treated field could almost be double to that of the B:C ratio of 2.91:1 obtained through F.P. operations.
Rice cultivation made by BIPM operation comprising of production and protection inputs supplied all from organic sources viz. vermicompost, neem and karanj cake to meet the requirement of N, P, K to the plants, seed treatments with Pseudomonas fluorescence and release of the egg parasitoid viz. Trichogramma japonicum @ 1.5 lakh/ ha , three times coupled with need based foliar spray of NSKE 5 per cent for protecting the crop against major insect pests especially YSB and leaf folder could be able to realize substantial yield of rice grains (33.75 q/ ha), net profit of Rs. 1,99,371/ ha with the higher benefit cost ratio of 5.42:1 through encouraging the population build-up of natural bioagents viz. spiders, coccinellids and mirid bugs without harming the balance of nature.
The experimental results of bio-efficacy evaluation of newer and novel molecules of insecticidal experiment indicated that the ready- mix combination products viz. spinetoram 6 SC + methoxyfenozide 30 SC @ 400 ml/ ha could be most effective against YSB followed by flubendiamide 240 SC + thiaclorprid 240 SC @ 220 ml/ha. However, novaluron 5.25 SC +indoxacarb 4.5 SC @ 750 ml/ ha remained most effective against leaf folder, followed by flubendamide 240 SC + thiaclorprid 240 SC @ 220 ml/ha. Ready mix combi product spinetoram 6 SC + methoxyfenozide 30 SC @ 400 ml/ ha treated rice plants gave rise to the highest grain yield of 52.48 q/ ha with net profit of Rs. 21,534/ ha with B:C ratio of 1.67:1. The combination product of novaluron 5.25 SC +indoxacarb 4.5 SC @ 750 ml/ ha gave rise to grain yield of 50.42 q/ ha with net profit of Rs. 20,975/ ha with highest B:C ratio of 2.24:1.
In nutshell, use of either of one of the best resistant rice varieties viz. Lalat, Naveen, CR Dhan 201, CR Dhan 303, CR Dhan 304, Suraksha, PAC-801, US-380 planted at an early date of 1st July, under the protection cover provided with need based foliar spray with any one of the combination products viz. spinetoram 6 SC + methoxyfenozide 30 SC @ 400 ml/ ha or novaluron 5.25 SC +indoxacarb 4.5 SC @ 750 ml/ ha could be able to realize substantial yield, net profit and B:C ratio. Aromatic rice grown through adoption of BIPM operation could be able to realize appreciable yield of grains (33.75 q/ ha), net benefit (Rs. 1,99,371/ ha), and benefit cost ratio of 5.42:1 with minimum no harm to the agro-ecologies through the organic method of rice cultivation.
Description
MANAGEMENT OF MAJOR LEPIDOPTERAN INSECT PESTS OF RICE