scholarly journals Effect of Weather Parameters on the Incidence of Thrips, Thrips tabaci Lindeman on Bt Cotton

Author(s):  
R. Sunitha Devi ◽  
S. G. Mahadevappa

The field experiments were conducted during kharif season of year 2014 & 2015 at Agricultural Research Station, Rajendranagar, Hyderabad, Telangana state, India to study the influence of weather parameters on the incidence of thrips population on Bt cotton. The results revealed that the peak incidence of thrips population was recorded on 35th Standard Week i.e., last week of August (32.87 thrips leaf–1) during kharif, 2014 and two peaks i.e., 35th Standard Week i.e., last week of August (33.93 thrips leaf–1) and 40th  Standard Week i.e., the first week of October (40.40 thrips leaf–1) were recorded during kharif, 2015. Thereafter, its population declined gradually during both seasons. Correlations worked out between thrips population and weather parameters revealed that, one week (0.51*) and two weeks lag (0.65**) minimum temperature, one week lag (0.56**) morning relative humidity showed significant and positive influence, while one week lag (–0.44*) evaporation showed significant negative influence on thrips incidence. The prediction model developed for the thrips population revealed that the model explained the variation to an extent of 54 per cent in thrips incidence under the influence of minimum temperature and morning relative humidity.

Author(s):  
Nayan Kishor Adhikary ◽  
Krishnendu Roy ◽  
Kajal Kumar Biswas

Sesame is one of the most important oilseed crops in India due to mainly its high quality seed oil and antioxidant properties. Occurrence of foliar diseases, like Alternaria leaf spot and Cercospora leaf spot has become a major constraint in recent years for successful and profitable cultivation of sesame. Field experiments were conducted with sesame var. savitri in a factorial randomized block design with three different dates of sowing with 15 days interval and two different plant protection situations (Protected i.e., treated with disease control protocols and unprotected i.e., control), replicated four times, during two consecutive summer seasons of 2018 and 2019 at Agricultural Experimental Farm, Institute of Agricultural Science, University of Calcutta, Baruipur, South 24 Parganas. The diseases incidence was estimated and correlated with the weather parameters. The average of weather parameters viz., maximum temperature, minimum temperature, relative humidity (morning), relative humidity (evening) and rainfall prior to seven days of disease appearance were considered for study the correlation between the weather factors and the disease. In 2018, disease incidences of the plants shown at third date of sowing (26th April, 2018) in both the protected and unprotected plots had significant (P=.05) but negative correlation with maximum temperature. For plants sown at first date of sowing (27th March, 2018) in 2018 had disease incidences significantly (P=.05) and positively correlated with minimum temperature. However, in 2019, except for the relation between disease incidences in the unprotected plots and maximum temperature, all other disease-temperature correlations were non-significant. Disease incidences were positively and significantly correlated with relative humidity (both morning and evening) in all dates of sowing irrespective of experimental years, except with morning relative humidity at first date of sowing in first year. Total rainfall was positively and significantly correlated with disease incidences at all dates of sowing in 2018; however, such relation was non-significant in 2019. 


2016 ◽  
Vol 8 (4) ◽  
pp. 2262-2267
Author(s):  
Parmod Verma ◽  
Ranbir Singh Rana ◽  
Ramesh Ramesh ◽  
Ranu Pathania

The study assessed the sensitivity of weather parameters with respect to total green leaf and two leaves and bud (T & B) productivity of tea crop {Camellia sinensis (L.) Kuntze}. The maximum temperature ranging from 20.0 to 29.0 oC during March, May, August and September showed positive relationship with values ranging from 0.26 to 3.38 and 0.22 to 3.22 for green leaf and T & B yield, respectively. Similarly, minimum temperature ranging from 9.1 to 20.0 oC during March and July to October found positive 0.001 to 2.93 and 0.28 to 2.91 for green leaf and T & B productivity, respectively. The mean monthly rainfall amounting 52.7 to 664.7 mm during March, May, July to October and 52.7 to 488.4 mm during June, July, September and October also showed positive sensitivity with values ranging from 0.03 to 0.33 and 0.007 to 0.35 for green leaf and T & B yield, respectively. The relative humidity ranging between 41.2 to 77.3% during April to May for green leaf yield (0.32 to 1.71) and during April to May and October for two leaf and bud yield (0.00 to 1.70) showed positive relationship. So, maximum and minimum temperature between 20.0 to 29.0 oC and 9.1 to 20.0 oC, respectively with rainfall of 52.7 to 488.4 mm and relative humidity 41.2 to 77.3% are the most beneficial weather parameters for tea cultivation at Palampur conditions.


Author(s):  
Kasthuri Rajamani ◽  
A. Madhavi ◽  
T. Srijaya ◽  
P. Surendra Babu ◽  
Pradip Dey

Field experiments were conducted from 2015-16 to 2017-18 on a Typic Rhodustalfs (Alfisol) soils of Telangana at Regional Agricultural Research Station, Palem, Nagarkurnool, Southern Telangana Zone, India to validate targeted yield based fertilizer prescription equations which developed for hybrid castor by adopting eight treatments viz., Blanket recommendation (100% RDF:80:40:30 kg N, P2O5 and K2O ha-1), Blanket+5 t ha-1 of vermin-compost (VC), STCR-Target yield with NPK alone at 25q ha-1, STCR-Target yield with IPNS at 25q ha-1, STCR-Target yield with NPK alone at 30q ha-1, STCR-Target yield with IPNS at 30q ha-1, Farmer’s practice (40:20:0kg N, P2O5 and K2O ha-1) and Absolute control (without inorganic and organic fertilizers). The findings of these test verification trials clearly revealed that the percent achievement of the aimed yield target was within + 10 percent variation confirming the validity of the equations. Using STCR-NPK@25 and 30q ha-1 recorded significantly higher seed (20.74 and 22.30q ha-1) and stalk (24.63 and 26.36q ha-1) yield over blanket recommendation (19.40 and 23.13 q ha-1), while STCR-IPNS at 25 and 30 q ha-1recorde relatively higher seed (20.98 and 22.69q ha-1) and stalk (25.88 and 27.13q ha-1) yield over STCR-NPK alone treatments. The magnitude of built-up was higher with STCR-IPNS treatments as compared to STCR-NPK alone, blanket recommendations, farmer’s practice and absolute control.


Author(s):  
Elsayed Omer ◽  
Saber Hendawy ◽  
Abdel Nasser ElGendy ◽  
Alberto Mannu ◽  
Giacomo L. Petretto ◽  
...  

A relevant improvement of the cultivar conditions of Rosmarinus officinalis L. in desert areas was achieved by a specific combination between irrigation system and soil conditioner. A drastic reduction of water employment was obtained without affect the quality of the plants, determined by monitoring growth parameters and essential oil characteristics. In particular, the effect of surface and subsurface drip irrigation systems and different soil conditioners on growth parameters, yield, and essential oil constituents of rosemary plant was assessed. Field experiments at the Agricultural Research Station (Al-Adlya farm), SEKEM group Company, El-Sharkiya Governorate, Egypt, conducted over the two seasons revealed the effectiveness of the subsurface irrigation system in obtaining better performances, especially in terms of water saving. The combination of subsurface irrigation and the conditioner Hundz soil with bentonite showed the maximum mean values of growth characters compared with other soil amendments during both seasons. The possibility to employ a water-saving irrigation system as the subsurface one without any drawback in the resulting plants was also explored in terms of molecular composition. GC-MS analysis of the essential oil extracted from plants growth under different irrigation conditions revealed a comparable composition in both cases. The goodness of the most performing system was also confirmed by the comparable yield of the essential oil.


2020 ◽  
Vol 12 (8) ◽  
pp. 212
Author(s):  
A. M. Sheha ◽  
Haytham Mostafa El-Shahed ◽  
Abd El Nabi Hamed Mohamed Diab

Two field experiments were carried out at the Experimental Farm of Gemmeiza Agriculture Research Station, Agricultural Research Center (ARC), Egypt after 2018 and 2019 summer growing seasons to determine the effect of intercropping pattern of yellow maize hybrid (single cross 168: “SC 168”) with watermelon pulp at three plant distributions (20 cm between hills and one plant/hill, 40 cm between hills and two plants/hill and 60 cm between hills and three plants/hill) and different levels of nitrogen fertilizer (25, 50, 75 and 100% of the recommended dose “120 kg N fad-1”) as well as their interactions on maize and watermelon pulp growth, yield and its attributes as well as competitive relationships and yield advantages. The experiments were carried out in split-plot design with four replicates. The main-plots were assigned to plant distributions of maize, the sub-plots were allocated to levels of nitrogen fertilizer for maize. The obtained results showed that planting maize plants on one side of terraces of 140 cm width with 20 cm between hills and leaving one plant/hill and planting watermelon pulp on the other side of the terraces produced the highest values of plant height, ear height, number of kernels row-1, 100-kernel weight and grain yield fad-1, at the same time the lowest values of ear leaf area, ear length, ear diameter and number of rows ear-1 of maize as well as the lowest values of growth, yield and its attributes of watermelon pulp during the both seasons. Mineral fertilizing maize plants with 75% of the recommended dose (90 kg N/fad) and watermelon pulp with the recommended dose produced the highest values of all studied growth characters, yield and its attributes of maize and watermelon pulp in both seasons. The highest values of land equivalent ratio (LER), relative crowding coefficient (RCC), area time equivalent ratio (ATER), land equivalent coefficient (LEC), aggressivity index (AI), monetary advantage index (MAI), actual yield (L.E.) of watermelon, Total income (L.E.) and economic return (L.E.) were obtained from planting maize plants on one side of terraces of 140 cm width with 60 cm between hills and leaving three plants/hill and planting watermelon pulp on the other side of the terraces besides fertilizing maize plants with 75% of the recommended dose (90 kg N/fad) and watermelon pulp with the recommended dose in both seasons. It can be recommended that planting maize on 60 cm between hills and leaving three plants/hill and planting watermelon pulp on the other side of the terraces besides fertilizing maize plants with 90 kg N/fad and watermelon pulp with the recommended dose to obtain the maximum values growth, yield and its attributes of watermelon pulp and competitive relationships and yield advantages of both crops under the climates conditions of Middle Delta, Egypt.


MAUSAM ◽  
2022 ◽  
Vol 73 (1) ◽  
pp. 173-180
Author(s):  
NAVNEET KAUR ◽  
M.J. SINGH ◽  
SUKHJEET KAUR

This paper aims to study the long-term trends in different weather parameters, i.e., temperature, rainfall, rainy days, sunshine hours, evaporation, relative humidity and temperature over Lower Shivalik foothills of Punjab. The daily weather data of about 35 years from agrometeorological observatory of Regional Research Station Ballowal Saunkhri representing Lower Shivalik foothills had been used for trend analysis for kharif (May - October), rabi (November - April), winter (January - February), pre-monsoon (March - May), monsoon (June - September) and post monsoon (October - December) season. The linear regression method has been used to estimate the magnitude of change per year and its coefficient of determination, whose statistical significance was checked by the F test. The annual maximum temperature, morning and evening relative humidity has increased whereas rainfall, evaporation sunshine hours and wind speed has decreased significantly at this region. No significant change in annual minimum temperature and diurnal range has been observed. Monthly maximum temperature revealed significant increase except January, June and December, whereas, monthly minimum temperature increased significantly for February, March and October and decreased for June. Among different seasons, maximum temperature increased significantly for all seasons except winter season, whereas, minimum temperature increased significantly for kharif and post monsoon season only. The evaporation, sunshine hours and wind speed have also decreased and relative humidity decreased significantly at this region. Significant reduction in kharif, monsoon and post monsoon rainfall has been observed at Lower Shivalik foothills. As the region lacks assured irrigation facilities so decreasing rainfall and change in the other weather parameters will have profound effects on the agriculture in this region so there is need to develop climate resilient agricultural technologies.


2021 ◽  
Vol 17 (AAEBSSD) ◽  
pp. 17-26
Author(s):  
R. Bala Muralidhar Naik ◽  
K. Vijaya Lakshmi ◽  
M. Venkataiah ◽  
C. Srinivas ◽  
G. Uma Devi ◽  
...  

The field experiment was carried out at Polasa Farm, Regional agricultural research station Jagtial during the Kharif, 2014-15 and 2015-16. Study about pre dominant lepidopteran insect –pests in soybean crop noticed that the tobacco cut worm, (Spodptera exigua Hubner), green semi looper(Crysodexis acuta Walker), and tobacco caterpillar (Spodoptera litura Fab) along with stemfly, (Melanagromyza obtusa Zehnter) as non lepidopteran pest were noticed at various growth stages of cropgrowth. The peak activity of stem fly (37.84%) was observed during 37th standard week per meter row) for the year 2014 and for the year 2015 to a maximum infestation of 35.70 per cent during 30th std.week. The peak activity of caterpillar pests i.e., S. litura (7.6 larvae per meter row) for the year 2014 was observed during 34th std.week and for the year 2015 (12.4 per meter row during 36th std.week and C. acuta (0.7 larvae per meter row) during 36th std. week for the year 2014 and for the year 2015 (2.20 larvae/mrl on 37th std week. S. exigua (1.6 larvae per meter row) for both the years 2014 and 2015 was observed during 32th std.week Among the natural enemies, one predators namely, spiders (Oxyopes sp. was observed to prey on the insect pests.The biocontrol agent’s one species, lynx spider, Oxyopes sp. population recorded on the crop during Kharif , 2014 ranged from 0.15 to 0.40 /mrl and 0.15 to 0.60/ mrl during Kharif, 2015.


Author(s):  
M. Sreekanth ◽  
M. Seshamahalakshmi ◽  
M. V. Ramana

Background: Pod fly, Melanagromyza obtusa is one of the most obnoxious pest causing grain damage ranging from 10-80% with a monitory loss of US$ 256 million annually. Being an internal feeder, infested pods do not show any external symptoms of damage until the fully grown maggots chew the pod wall, leaving a thin papery membrane intact called as window, through which adults exit from the pod. Several field studies were conducted to determine the efficacy of insecticides for the control of pod fly. However, these findings did not find acceptability and led to partial success. Insecticides that should leave lesser residues and pose lesser environmental threat have become imperative. The present study aimed to evaluate the efficacy of certain new insecticide molecules against pod fly in pigeonpea ecosystem. Methods: Two field experiments were conducted at Regional Agricultural Research Station, Lam, Guntur during Kharif, 2012 and 2013 in a randomized block design (RBD) using pigeonpea cv. ICPL 85063 (Lakshmi) with 17 treatments including untreated control and 3 replications. Two sprays were given at 10 days interval starting from pod initiation stage. At maturity, number of pods showing pod fly damage were recorded and expressed as percentage. Grain yield was recorded and cost–benefit ratio was worked out. Result: Among different insecticides, thiacloprid 21.7 SC, followed by diafenthiuron 50 WP, flubendiamide 480 SC and dimethoate 30 EC were very effective against pod fly with more grain yield and registered highest incremental cost benefit ratio (ICBR). It was further suggested that effective insecticides may be alternated in order to avoid development of resistance to pod fly in pigeonpea.


2021 ◽  
Vol 58 (1) ◽  
pp. 15-20
Author(s):  
ADVSLP Anand Kumar ◽  
N Mallikharjuna Rao ◽  
CV Rama Rao ◽  
S Krishnam Raju

A field experiment on the population dynamics of White backed planthopper (WBPH), Sogatella furcifera (Horvath) carried out during kharif and rabi 2016-17 at Regional Agricultural Research Station, Maruteru, West Godavari District of Andhra Pradesh, India revealed that the incidence of WBPH was observed during 36th SMW (September 3-9). Its activity increased during successive weeks up to 44th SMW with two peaks, first peak at 38th SMW (September 17-23) with population of 46/10 hills and second peak at 42nd SMW (October 15-21) with population of 170/ 10 hills during kharif 2016, while WBPH was first noticed during 7th SMW (February 12-18) and population increased gradually during successive weeks and attained peak number during 13th SMW (March 26-April 1) in rabi 2016-17. Correlation studies revealed that WBPH had significant negative relation with morning relative humidity of current week during kharif 2016. None of the abiotic factors has showed significant relationship with the population of WBPH during rabi 2016-17.


2010 ◽  
Vol 28 (2) ◽  
pp. 239-246 ◽  
Author(s):  
J. Gherekhloo ◽  
S. Noroozi ◽  
D. Mazaheri ◽  
A. Ghanbari ◽  
M.R. Ghannadha ◽  
...  

Two field experiments were conducted to evaluate the effects of multispecies weed competition on wheat grain yield and to determine their economic threshold on the crop. The experiments were conducted in 2002, on two sites in Iran: at the Agricultural Research Station on Ferdowsi University of Mashhad (E1) and on the fields of Shirvan's Agricultural College (E2). A 15 x 50 m area of a 15 ha wheat field in E1 and a 15 x 50 m area of a 28 ha wheat field in E2 were selected as experimental sites. These areas were managed like other parts of the fields, except for the use of herbicides. At the beginning of the shooting stage, 30 points were randomly selected by dropping a 50 x 50 cm square marker on each site. The weeds present in E1 were: Avena ludoviciana, Chenopodium album, Solanum nigrum, Stellaria holostea, Convolvulus spp., Fumaria spp., Sonchus spp., and Polygonum aviculare. In E2 the weeds were A. ludoviciana, Erysimum sp., P. aviculare, Rapistrum rugosum, C. album, Salsola kali, and Sonchus sp. The data obtained within the sampled squares were submitted to regression equations and weeds densities were calculated in terms of TCL (Total Competitive Load). The regression analysis model indicated that only A. ludoviciana, Convolvulus spp. and C. album, in E1; and A. ludoviciana, S. kali, and R. rugosum, in E2 had a significant effect on the wheat yield reduction. Weed economic thresholds were 5.23 TCL in E1 and 6.16 TCL in E2; which were equivalent to 5 plants m-2 of A. ludoviciana or 12 plants m-2 of Convolvulus spp. or 19 plants m-2 of C. album in E1; and 6 plants m-2 A. ludoviciana, 13 plants m-2 S. kali and 27 plants m-2 R. rugosum in E2. Simulations of economic weed thresholds using several wheat grain prices and weed control costs allowed a better comparison of the experiments, suggesting that a more competitive crop at location E1 than at E2 was the cause of a lower weed competitive ability at the first location.


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