Meteorological Week Research Articles

Seasonal Incidence of Whitefly Bemisia tabaci (Genn.) on Mungbean

This study on the seasonal incidence of whitefly Bemisia tabaci (Gennadius) on mungbean was done during kharif, 2014. Weekly observations on incidence were made on five randomly selected tagged plants. The results revealed that the first incidence was observed during 22nd standard meteorological week (SMW)- 66.67 whitefly/plant. This reached at its peak (89.67 whitefly/plant) during the 34th SMW. Correlation coefficients between incidence and weather factors revealed that maximum temperature had a positive relationship (r = 0.51) while the minimum temperature and relative humidity- RH (morning) revealed a negative one (r = -0.03 and r = -0.52); and RH (evening) and rainfall showed a highly significant but negative correlation.

Seasonal Incidence of Pea Leaf Miner Chromatomyia horticola Goureau Infesting Garden Pea

The seasonal incidence of pea leaf miner Chromatomyia horticola Goureau, on garden pea (Pisum sativum L.) was assessed during 2017 and 2018 at the research farm of Sher-e-Kashmir University of Agricultural Sciences and Technology of Jammu, Chatha. The pooled data revealed that the incidence show continuous fluctuation, with first appearance being during the 49th standard meteorological week (SMW)-0.95 miners/leaf which reached its peak (11.00 miners/leaf) during the 4th SMW, then reached to minimum (1.26 miners/leaf) during the 12th SMW. The correlation studies indicated highly significant negative association between incidence and maximum temperature (-0.714**), significant positive one with evening relative humidity (RH) (0.544*); and non-significant ones with minimum temperature (-0.385) and wind speed (-0.74), morning RH (0.258), sunshine (0.013) and rainfall (0.356).

Management of Pink Bollworm Pectinophora gossypiella (Saunders) in Cotton

Demonstrations were conducted to assess the damage potential caused by the pink bollworm Pectinophora gossypiella (Saunders) and its management strategies were worked out through technology demonstration and check (farmer’s practice). Results revealed that >10% rosette flowers were observed, starting from 36th standard meteorological week (SMW) up to 2nd SMW except during 49th to 52nd SMW. In contrast, in control, maximum incidence was during October Ist fortnight (25.92%). Incidence of larvae on green bolls of Bt cotton was noticed from first fortnight of September (36th SMW) (8.4 larvae/50 bolls) with a peak during the second fortnight of December (51st and 52nd SMW) (19.2 larvae/50 bolls; the green boll damage ranged from 8.9 to 18.4 with a mean of 14.72% in treatment and 12.6 to 20.8 with a mean of 28.38% in control, respectively. Significantly higher income was obtained with the technology demonstrated plots, with high benefit cost ratio.

SELECTION OF POTATO APICAL LEAF CURL VIRUS DISEASE-RESISTANT GENOTYPES, PEST SURVEILLANCE, SEED DEGENERATION, AND MANAGEMENT OF APHID IN FIELD CONDITIONS

Objectives: Under All India Co-ordinated Research Project on Potato, studies on the selection of potato apical leaf curl virus disease-resistant genotypes, pest surveillance, seed degeneration, and management of aphid in field conditions were conducted at Hisar during 2017–2018. Methods: Sowing of seed tubers was done at recommended time and spacing in every experiment followed by spraying of required insecticides. Observations on different aspects were recorded and statistically analyzed to present results in tabular format. Results and Discussion: Out of 100 germplasm, seven were resistant and one was moderately resistant to potato apical leaf curl New Delhi virus, all the local genotypes were susceptible to disease. There was infestation of aphids, jassids, thrips, and whitefly irrespective of cultivars. Severe mosaic incidence ranged from 63.6 to 93.2%. The breeder seed was superior as it resulted in the highest seed tuber emergence (98.94%) and the least incidence of leafroll disease (0.80%) followed by seed tuber of seed plot technique (SPT). The conventional seed performed the poorest in terms of emergence and exhibited the highest disease incidence. Aphid appeared in the 47th meteorological week and it approached the ET level in the 52nd week. Whitefly population was the highest in the 47th week which continuously declined. Jassid population was very mild and thrips appeared in the 52nd week. Flonicamid 50 WG caused higher aphid mortality than imidacloprid after 24 h of spray. The maximum and minimum temperatures varied from 16.9 to 35.7 and 2.6 to 16.2° C, respectively. The morning and evening relative humidity was in the range of 82–100 and 24–75%, respectively. The wind speed ranged from 1.0 to 3.6 KMPH and the sun was shined from 0.3 to 7.6 h. The results of this study are close conformity of earlier researchers. Conclusion: It is concluded that resistant genotypes, breeder seed, and seed produced through SPT are promising in managing the disease successfully. Flonicamid is a good alternative of imidacloprid. Aphid is a major pest that plays a key role in transmitting viral disease of this crop, its population touched ET level in the 52nd week.

Effects of Date of Transplanting on The Incidence of Rice Leaf Folder Cnaphalocrocis medinalis (Guenée) and its Population Dynamics

Field studies were conducted to evaluate the impact of transplanting dates and weather parameters on the incidence of rice leaf folder Cnaphalocrocis medinalis (Guenee). During 2018 kharif season, the first incidence was noticed during 27th standard meteorological week (SMW) irrespective of the transplanting dates, with peak being in the 28th SMW (1.67% damaged leaves/hill). Least damage was observed in 4th date of transplanting (20th July), while maximum incidence was with 20th June transplanting. The correlation of incidence with temperature showed negative correlation, while rainfall and relative humidity showe positive relationship.

Effect of Sowing Dates on Yield Attributes, Yield and Economics of Linseed (Linum usitatissimum L.) Varieties

A field experiment was conducted during the rabi season of 2020-2021 at Agronomy farm, College of Agriculture, Nagpur to study the effect of sowing dates on yield attributes, yield and economics of linseed varieties. The treatment comprised of four sowing dates, i.e., 43rd meteorological week (22nd October - 28th October), 44th MW (29th October - 4th November), 45th MW (5th November - 11th November) and 46th MW (12th November - 18th November) in main plots and three varieties i.e., PKV-NL-260, PKV-NL-97 and JLS-73 in sub-plots, replicated three times in a split plot design. Sowing dates as well as varieties significantly affect yield attributes, yield and economics of linseed. The result of the experiment showed significantly higher number of capsule plant-1 (52.89), number of seed capsule-1 (8.11), seed yield (9.13 quintal/hectare), biological yield (25.45 q ha-1) and harvest index (35.87%), gross monetary return (Rs. 44688 ha-1) and net monetary return (Rs. 23436 ha-1) with benefit cost ratio (2.10) were recorded when crop sown during 44th MW. The variety PKV-NL-260 recorded significantly higher number of capsule plant-1 (48.08), number of seed capsule-1 (8.25), seed yield (8.85 q ha-1), biological yield (24.92 q ha-1) and harvest index (35.52%), gross monetary return (Rs. 43478 ha-1) and net monetary return (Rs. 22226 ha-1) with benefit cost ratio (2.04). The sowing date on 44th MW along with variety PKV-NL-260 was found significantly higher seed yield (9.95 q ha-1), gross monetary return (Rs. 48225 ha-1) and net monetary return (Rs. 26973 ha-1). Linseed crop sown during 44th MW along with variety PKV-NL-260 performed better than variety PKV-NL-97 and JLS-73.

Seasonal Incidence of Striped Flea Beetle Phyllotreta striolata F. on Cruciferous Crops in North Kashmir

This study is on the seasonal incidence of Phyllotreta striolata F. during 2015 and 2016, on turnip (Brassica rapa var. rapa), radish (Raphanus sativus) and cabbage (B. oleracea var. capitata). The incidence observed at weekly intervals was correlated with weather factors. The pest was first observed during 35th standard meteorological week (SMW), and in 2015, peak was observed on turnip (22.8 beetles/ plant) and radish (22.2 beetles/ plant) during the 40th SMW; during 2016, peak was (19.4 beetles/ plant on turnip; 22.2 beetles/ plant on radish) in the 39th SMW; and on cabbage, the peak incidence (4.8 beetles/ plant- 2015; 9.2 beetles/ plant - 2016) was during 38th SMW. The incidence showed a positive correlation with temperature and sunshine hours, and a negative correlation with relative humidity and rainfall.

Growth and Correlation with Weather Parameters as Affected by Transplanting Time and Different Varieties of Paddy (Oryza sativa L.)

Background: Time of planting is the most important factor in influencing the yield of the crop. Performance of genotype entirely depends upon the time of planting. For obtaining higher paddy production study of crop for transplanting time and different varieties concerning weather parameters are very necessary. Methods: Experiment was laid out in a split-plot design with three replications at Agriculture Research Station Farm, Vadgaon-Maval, Tal-Maval, Dist-Pune (M.S.) during Kharif, 2013 to study effect of transplanting time on different varieties of paddy concerning weather parameters. 48 treatment combinations were comprised of 4 transplanting times viz., 26th, 28th, 30th and 32nd meteorological weeks and four varieties viz., VDN-3-51-18, VDN-99-29, IET-13549 and RDN-99-1. Result: Transplanting of Kharif paddy during 28th MW improved plant growth. Variety VDN-99-29 recorded significantly higher plant growth. Among the interaction, when the VDN-99-29 variety of paddy was transplanted during 28th MW produced significant effect on plant growth. Correlation indicated that maximum temperature, bright sun hour and growing degree days showed significant and negative co-relationship with plant-growth, minimum temperature, RH-I and RH-II showed positive and significant correlation with growth.

Studies on finding agroclimatic normals for getting maximum yield in maize hybrids under rainfed condition

Field experiment was conducted from 2009 - 16 at Agricultural Research Station, Kovilpatti to find the optimum weather requirement for getting higher growth, development and grain yield of maize hybrid under rainfed condition. Experiments were laid out in split-plot design with three replications. The treatment combinations comprised of four dates of sowing viz., 39th, 40th, 41st and 42nd standard meteorological weeks in main plot with three different maize hybrid viz., 900(M) GOLD, NK6240 and Prabal in sub plot. Pooled analysis revealed that maize hybrid sown during 39th standard meteorological week recorded higher grain yield (3548 kg ha-1) followed by 40th standard meteorological week sowing (3307 kg ha-1). The lower grain yield was obtained with when the maize crop was sown during 42nd standard meteorological week (2738 kg ha-1). Among different varieties, NK 6240 recorded the higher grain yield (3619 kg ha-1). The correlation analysis revealed that, minimum temperature at vegetative, silking, milking, dough and maturity stages affect the grain yield negatively. Rainfall at vegetative stage affected the grain yield positively. Evaporation at vegetative, milking, dough and maturity phases negatively influenced the grain yield. The optimum weather parameters viz., minimum temperature at milking phase is 17.5 - 19.5 oC, rainfall at knee high stage is between 150 - 200 mm, the relative humidity at tasseling stage is between 85 - 90 % and the evaporation at milking stage is between 2.5 and 3.5 mm/day were required to get higher grain yield of maize under rainfed condition.

Seasonal variation in population and biochemical contents of brown planthopper, Nilaparvata lugens (Stål)

Aim: The present study was undertaken on population dynamics and estimation of protein, water-soluble carbohydrates and glycogen contents in the brown planthopper, Nilaparvata lugens to explore their migratory behaviour. Methodology: Brown planthopper populations were monitored and collected using sweep nets from 23rd standard meteorological week (SMW) to 47th SMW during 2017 and 2018 rainy seasons to understand population dynamics of the pest. The protein, water-soluble carbohydrates and glycogen contents were estimated from the pest samples collected during 36th to 44th SMW in 2017 and 2018 rainy seasons. Results: Brown planthopper population were not observed in rice farm during 23rd SMW to 28th SMW during two years of study. However, macropterous form of the pest first appeared in the farm during 29th SMW and peaked during 43rd SMW. Thereafter, population declined and disappeared after 47th SMW during both the years. Water-soluble carbohydrates and glycogen contents varied significantly different weeks which remained low during 36th-39th SMW, however, increased gradually towards the end of the rainy season 2017 and 2018. On the other hand, protein content significantly varied among different weeks unlike the trend of water-soluble carbohydrates and glycogen. Interpretation: The study revealed the absence of brown plant hopper during summer season preceding rainy season, and the accumulation of bio-chemical compounds towards the end of rainy season under Delhi environment is perhaps suggestive of migration of the pest from unknown areas during rainy season to Delhi and likely preparedness of the pest for emigration to safer areas from Delhi, respectively.

Population dynamics of important insect pests of Black gram and their correlation with abiotic factors

Black gram is an important pulse crop, which observes 30-50 % losses in yield due to insect pest damage. It is crucial to understand the spectrum of pest damaging it in field, and their response to the prevailing environmental conditions. Population dynamics of important insect pests and their correlation with abiotic factors was studied at CCS HAU, Hisar during kharif 2020. The study was carried out from July, 2020 i.e., 30th standard meteorological week (SMW) to October 2020 (39th standard meteorological week). Insect pests whose infestation was recorded during this period includes Bemisia tabaci, Empoasca kerri, Clavigralla gibbosa, Riptortus pedestris, Maruca vitrata and Trichoplusia ni. No infestation of Helicoverpa armigera and Spodoptera litura was recorded. Natural enemies like Coccinella septumpuctata and spiders were also observed. Out of these, whitefly was observed as most important insect pest causing significant damage to crop. Whitefly incidence commenced in 30th-SMW (19.70 adult/cage) and continued till 39th-SMW (13.35 adult/cage) with its peak population in 31st-SMW (41.75 adult/cage). Rainfall was recorded to be the major factor affecting the population of whitefly adult as significant and negative correlation was reported between the two (r = -0.682*). Further highly significant and negative correlation was observed between spotted pod borer larvae and wind speed (r = -0.792**). This study provides basic understanding about the range of pests damaging crop, and their behavior towards various abiotic factors.

Effect of meteorological parameters and natural enemies on population dynamics of rose aphid, Macrosiphum rosae L. under mid hills of Himachal Pradesh, India

The study revealed that the rose aphid first appeared in 8th standard meteorological week (SMW) and attained the first peak on 10th SMW, when maximum and minimum temperatures were around 20.5 and 5.9 (°C), respectively and morning relative humidity was 62.50% during both the years. The second mean population build-up was observed on 36th SMW and the population fluctuated between 37th to 52nd SMW and peak population was recorded on 51st SMW (29.05 aphids/shoot), which declined to 1.48 aphids/shoot on 52nd SMW during both years. The rose aphid population was significantly negatively correlated with Tmax (r = -0.453**) and Tmin (r = -0.572**); whereas relative humidity (morning and evening) and rainfall showed a nonsignificant negative correlation with the rose aphid population. The stepwise regression analysis of rose aphid population with weather parameters showed that the maximum temperature contributed 20.50% variation in rose aphid population followed by morning relative humidity (17.90%) and minimum temperature (12.70%). The difference between coefficient of multiple determination (R2) and adjusted R2 was less, indicating that the abiotic variables (Tmax: 0.017; Tmin: 0.030) have a significant effect on the rose aphid population. Hence, this study gives information on abiotic and biotic factors that naturally suppress the rose aphid, which helps develop management strategies against M. rosae in the mid-hills of Himachal Pradesh, India.

Population dynamics of major sucking insect pests on chilli (Capsicum annum L.)

Studies on population dynamics of major sucking insect pests revealed that the incidence of thrips, Scirtothrips dorsalis (Hood), whitefly, Bemisia tabaci (Gennadius) and leafhopper, Amrasca bigutulla bigutulla (Ishida) along with ladybird beetle, Coccinella septemtheirpunctata observed to appear on the chilli crop soon after transplanting. Incidence of thrips commenced in 19th Standard Meteorological Week (SMW) and attained its peak on 25th SMW (18.83 thrips /3 leaves /plant) while an infestation of whitefly was initiated in 20th SMW then it increased gradually and reached its peak on 25th SMW (21.20 whitefly/3 leaves /plant). The peak population of leafhoppers was recorded in 26th SMW (10.4 leafhopper /3 leaves /plant). In case of ladybird beetle, the population ranged from 0.20 to 0.93 per plant and was on the entire crop growth period (18th-37th SMW). Thrips and whitefly exhibited a highly significant positive correlation with maximum temperature, a negative non-significant correlation with evening relative humidity, and a non-significant correlation with wind speed, sunshine hours, and pan evaporation while a negative non-significant correlation with rainfall. Leafhopper population showed highly significant positive correlation with minimum temperature, non-significant negative correlation with maximum temperature, non-significant positive correlation with morning and evening relative humidity, sunshine hours, and rainfall while the negative non-significant correlation with wind speed and pan evaporation. Whereas, the ladybird beetle exhibited a positive non-significant correlation with maximum temperature, wind speed, sunshine hours and a negative non-significant correlation with minimum temperature, morning and evening relative humidity, pan evaporation, and rainfall.

Effect of biotic and abiotic factors on the incidence of major sucking insect pests of mothbean, Vigna aconitifolia (Jacq.) Marechal

A field experiment was conducted at Agronomy Farm, S.K.N. College of Agriculture, Jobner (Rajasthan) during Kharif, season 2019 - 20. To study the effect of biotic and abiotic factors on the incidence of major sucking insect pests of mothbean, Vigna aconitifolia (Jacq.) Marechal during Kharif, 2019 and 2020. The infestation of major insect pests, leafhopper, Empoasca motti Pruthi and whitefly, Bemisia tabaci (Genn), commenced in the second week of August in 2019 and first week of August in 2020 (32nd standard meteorological week, SMW) and reached their peak in first week of September. The population of leafhopper (r=0.71) and whitefly (r= 0.71, 0.72) revealed significant positive correlation with relative humidity in 2019 and 2020. The correlation of leafhopper (r=-0.76) and whitefly (r=-0.78) with maximum temperature was significantly negative in the second year only. The ladybird beetle, Coccinella septempunctata L. had significantly positive correlated with leafhopper (r=0.77, 0.76), whitefly (r=0.75, 0.82) and thrips (r=0.90, 0.75) during both years. The green lacewing population showed positive significant correlation with leafhopper (r=0.75, 0.76), whitefly (r=0.72, 0.79) and thrips (r=0.94, 0.80) during both the years.

Studies on Sowing Windows for Sustainable Production of Rabi Sorghum (Sorghum bicolour L.) Under Changing Climatic Condition in Scarcity Zone of Maharashtra

The field experiment was conducted at research farm, Zonal Agriculture Research Station, Solapur Mahatma Phule Krishi Vidyapeeth,Rahuri for five years (2016-17 to 2020-21) in rabi on sorghum entitled as “Studies on Sowing windows for Sustainable Production of Rabi Sorghum (Sorghum bicolour L.) Under Changing Climatic Condition in Scarcity Zone of Maharashtra.” to find out most optimum meteorological week for sowing sorghum in rabi season, to study the relationship between meteorological parameters and yield by using four different sowing windows. The results were obtained from the experiment; it was found that rabi sorghum sown at MW 40 (01-07 Oct) produced maximum pooled grain yield (808.28 kg ha-1), fodder (1494.11 kg ha-1) and total monetary returns (Rs. 26633 ha-1). Among the varieties, M-35-1 was produced significantly higher grain yield (717.94 kg ha-1), fodder yield (1559.03 kg ha-1) and total monetary returns (Rs. 24968 ha-1) over the other variety. The meteorological studies showed that the mean CUM and MUE recorded by sorghum crop was 240 mm and 2.7 kg ha-1 mm. The highest CUM was recorded by S1 sown crop (282 mm) however the MUE was recorded by S3 sown crop (3.5 kg ha-1 mm). This indicated that S3 sown crop (Chitra Nakshtras) utilized moisture more efficiently than other dates of sowing. Among the variety M-35-1 recorded maximum mean CUM (266 mm) and MUE (3.1 kg ha-1 mm) than other varieties. The number of days required to attain physiological maturity and growing degree days were higher in S3 sown crop. Among the varieties it is higher in M 35-1 than Mauli and Yashoda. In case of RUE initially values were low, it increases up to 70 DAS (i.e. up to 50 percent flowering to soft dough stage) further it decreases in all most all the sowing dates.

Effect of Changing Rainfall Situation on Yield of Pearl millet in Medium Deep Soil of Scarcity Zone of Maharashtra

The present invitation entitled “ Effect of changing rainfall situation on yield of pearl millet in medium deep soil of scarcity zone of Maharashtra.” was carried out during 2016-20 at Zonal Agricultural Research Station, Solapur, Mahatma Phule Krishi Vidyapeeth, Rahuri, Maharashtra (India). The experiment was conducted in split plot design with three replications. Nine treatment combinations were formed considering different cultivars viz., V1(ICTP-8203), V2 Mahyco Hybrid and V3 Dhanashakti and sowing windows viz., (S1) 2nd fortnight of June (25th June), (S2) - 2nd fortnight of July (27th-July) S3 - 2nd fortnight of August (24th - August). Among the three pearl millet sowing window crop sown in second fortnight of July (S2) produced significantly higher grain yield (1518.9 kg ha-1), biomass yield (2658.1 kg ha-1), total monetary returns (Rs. 33090 ha-1),CUM(383.7 mm), (MUE) (3.95 Kg ha-1 mm), GDD (1941-20610 days) and RUE (1.19g MJ-1) than other sowing dates. Among the genotypes Dhanashakti produced significantly higher grain yield (1369.9 kg ha-1), biomass yield (2525.5 kg ha-1) and total monetary returns (Rs. 29994 ha-1) than other cultivars. Under changing rainfall situation sowing of Kharif pearl millet contingent crop variety Dhanashakti upto 02nd September (Meteorological week no. 34-35) in medium deep soil of scarcity zone of Maharashtra is recommended for more sustainability in production. Following regression equation based on weather parameters for predicting the yield (prior to 2 weeks) is recommended. ÖYield= -101.38 + (-0.21 x Tmin) + (2.49 x RH-1) + (-1.34 x RH-2) + (0.08 x RF).

Analysis of Consecutive Days Maximum Rainfall Together With Dry, Wet Spell Rainfall for Crop Planning at Jorhat (Assam), India

In this study, frequency analyses of 1 to 6 consecutive days maximum rainfalls have been carried out. For this purpose, the daily rainfall data for 23 years has been collected from the Indian Meteorological Department (IMD), Guwahati for Jorhat Station. Based on L-moment, we consider the probability distributions like Log Normal (LN), Pearson Type III (P III), Log-Pearson Type III (LP III), and Extreme Value Type I (EVI). The best-fitting probability distribution for consecutive days maximum rainfall is discussed for estimating the rainfall in different return periods such as 2 to 100 years. Also, the daily rainfall data are converted to 52 standard meteorological weeks (SMW) to use the Markov Chain Probability model. Then average, maximum, minimum, standard deviation, and covariance of rainfall are calculated. By using this model, initial and conditional probabilities of dry and wet weeks are calculated. The probability of onset and withdrawal rainy season are calculated which are 95.83% chance during 23rd and 47th weeks. And, we find a relation of average rainfall and effective rainfall (ER) of the station.

Population Dynamics of Rice Insect Pests through Light Trap Catches and Its Relation to Abiotic Factors in High Altitude Tribal Zone of Seethampeta in Andhra Pradesh, India

Studies were carried out at Agricultural Research Station, Seethampeta in Andhra Pradesh during the kharif season for three consecutive years starting from 2017 to 2019 on the population dynamics of insect pests occurring in paddy and also to assess the influence of weather parameters on insect pests. The insect pests observed in the light trap catches were, Yellow stem borer, Gall midge, Leaf folder, Green leafhopper, Plant hopper (BPH/WBPH) and Grasshoppers. The light trap catches of rice insect pests were recorded at weekly interval during 32nd Standard Meteorological Week (SMW) to 52nd Standard Meteorological Week (SMW) and the data were correlated with the weather parameters. The results revealed that more number of adults of Yellow stem borer were noticed during the year 2019 from 45th to 48th SMW and the correlation studies revealed that that maximum temperature, minimum and maximum relative humidities had significant positive influence and regression value of R2 (743, 638 and 726 during 2017, 2018 & 2019). The population of gall midge was negligible during the year 2017 and 2018. Whereas, in 2019 peak was notice during 38th SMW (15 No’s) maximum relative humidity has positive relation with increase in the gall midge population. Leaf folder adults were trapped more in the light traps during the year 2019 with peak catches of 11.00 No’s on 42nd SMW and were positively correlated with maximum temperature, minimum and maximum relative humidities. Similarly, leafhopper, brown leaf hopper, grass hoppers were positively correlated with the relative humidity.

Seasonal incidence and efficacy of botanical insecticides against Painted bug, Bagrada hilaris (Burmeister) (Hemiptera: Pentatomidae) in Indian mustard (Brassica juncea genotype RH 725)

Bagrada hilaris (Burmeister) is a serious pest of Brassica crops in the North-Western region of India, inflicting crop yield losses. Therefore, the present study was conducted on seasonal incidence and management of B. hilaris in Brassica juncea genotype RH 725 at farmer’s field, Kolana village, Aravalli Hills Region, Rewari, Haryana, India during Rabi, 2019-20 and 2020-21. This study laid out the trial in a randomized block design with three replications and six treatments viz., Neem Seed Kernel Extract (NSKE) @ 7%, Nimbecidine @ 0.03%, Neem oil @ 5%, NSKE @ 5%, Neem oil @ 7% and control (unsprayed). Observations on the incidence of B. hilaris showed that it appeared from 5th Standard Meteorological Week (SMW) (0.34 bugs plant-1) and attained peak during 10th SMW with 5.77 bugs plant-1. The incidence of B. hilaris exhibited significant positive correlation with maximum (r=0.852, p<0.05) and minimum (r=0.900, p<0.05) temperature, rainfall (r=0.763, p<0.05) and wind velocity (r=0.959, p<0.05). Spray of Neem oil @ 7% (83.01 %) was the most effective in reducing the B. hilaris population over control followed by NSKE @ 7% (81.48 %), while NSKE @ 5% (68.85 %) confirmed least effective. Seed yield in different treatments varied from 1440.5 kg ha-1 (NSKE @ 5%) to 1590 kg ha-1 (Neem oil @ 7%) against 1216 kg ha-1 in control. The highest incremental cost-benefit ratio was registered with NSKE @ 7% (1: 7.70) followed by Nimbecidine @ 0.03% (1: 7.41) and NSKE @ 5% (1: 6.25). The present investigation signified that the study on the seasonal incidence of B. hilaris in relation to weather parameters could provide information for planning pest control and management strategies. The botanicals could be used as eco-friendly and economical substitutes for chemical insecticides at farmer’s fields against this insect pest.

Effect of weather parameters on the seasonal dynamics of tobacco caterpillar, Spodoptera litura (Lepidoptera: Noctuidae) in castor in Telangana State

Field experiments were carried out for four years (2012-13 to 2015-16) to study the seasonal dynamics of tobacco caterpillar, Spodoptera litura in castor and its relationship with different weather parameters during kharif season in Telangana State. Moth catches of S. litura were observed throughout the crop season, wherein maximum catches (44.8 to 124 moths/trap/week) were observed during mid- August to late-October [33rd to 43rd Standard Meteorological Week (SMW)]. Peak oviposition (2.0 to 14.8egg-masses/5 plants) and larval incidence (14.4 to 48 larvae/5 plants) of S. liturawas recorded during mid-August to mid-November (33rd to 46th SMW) coinciding with the vegetative to primary spike development stage of the crop. The correlation analysis indicated that the moth catches and larval population of S. litura showed significant positive correlation with weather parameters viz., maximum temperature, minimum temperature, rainfall and rainy days, while egg-masses of S. litura showed significant negative correlation with morning relative humidity and minimum temperature.The stepwise regression analysis revealed that minimum temperature, rainy days, wind speed and evening relative humidity could explain 64 per cent variation in S. litura moth catches. Among all the variables morning relative humidity was found to contribute significantly and showed 59 per cent effect on the population fluctuation of eggmasses, while rainy days and maximum temperature could explain 51 per cent variation in larval population of S. litura in castor.The models were validated with independent data 2015-16. The overall results suggested that the models can be used for predicting the population of S. litura in castor for optimizing management strategies.