Seasonal incidence of major insect pests and predators of mustard in lower gangetic plains of West Bengal

Abstract

The present investigation was carried out during rabi, 2019-20 at Jaguli instructional farm of Bidhan Chandra Krishi Viswavidyalaya by using four varieties (ADV414, Bulet, TBM 204 and ADV 406) of rapeseed-mustard. Altogether two insects viz., mustard aphid (Lipaphis erysimi) and sawfly (Athalia lugens proxima) cause most of the damages at different crop growth stages. In the middle of January maximum intensity of sawfly was observed when the crop was flower bud formation stage. Maximum aphid population was noticed during 2 nd week of February at silica formation stage of the crop irrespective of the varieties. The aphid population was very strongly correlated with the incidence of coccinellid population. The correlation study between sawfly population and weather parameters revealed that maximum and minimum temperature had significant negative correlation with the pest population. Among the weather parameters minimum relative humidity showed significant negative correlation with the aphid and coccinellid population. Regression studies indicated that temperature and relative humidity were the most influencing factors over the incidence of sawfly and aphid population respectively.

Abundance and Dispersion Indices of Helicoverpa armigera (Lepidoptera: Noctuidae) on Tomato Plant in Nigeria

“…It was reported that H. armigera larvae prefer unripe fruits to leaves and ripe fruits (Czepak et al, 2013;Queiroz et al, 2018). Our findings agree with Murúa et al (2014) who reported that H. armigera larvae prefer green fruits, as well as that of Mondal et al (2019) H. armigera larvae reach their peak period during the fruiting stage. However, our findings contradict reports of Chula et al (2017) who observed a high larval population of H. armigera during the entire crop period and the finding of Perkin et al (2010) which reveals that H. armigera larvae prefer the vegetative part of plants over fruits.…”

A review on seasonal succession and management of key insect- pest infesting tomato

“…Safna et al (2018 b) recorded the initiation of pests in the first week of January with a peak larval population during the 11 th SMW (March) with a temperature from 32.02 to 14.91 °C, a relative humidity of 68.28 (morning) and 66.29 (evening). Bhanuparkash et al (2019) found that the occurrence of H. armigera started from the 6 th standard week (February) and reached peak level in the 12 th standard week (March) with a larval population of 5.98 larvae per plant when the temperature ranges from 34.4 °C (max) to 16 °C (min) and a relative humidity of 88% (morning) and 47% (evening), while Mondal et al (2019) observed the tomato fruit borer population from the 7 th standard week to the 15 th standard week having weather parameters, such as the temperature in the range of 36.07 to 18.11 °C, a relative humidity of 49 % and no rainfall. Kachave et al (2020) recorded the incidence occurence from the 32 nd SMW with a larval population of 0.5 larvae/ plant to the 47 th SMW (1.5 larvae/ plant) and a peak in the 41 st SMW with a max.…”

“…Deb and Bharpoda (2017) noticed the aphid population from the 42 nd SMW with the highest population in the 52 nd SMW while Ghosh (2017) demonstrated a high population (0.62-2.69 aphids/leaf ) during the 41 st standard week (2 nd week of October) to the 51 st standard week (3 rd week of December) along with two more peaks in the 6 th SMW (2 nd week February) to 17 th SMW (4 th week of April). According to Mondal et al (2019), the aphid infestation started in the 2 nd week of January along with a peak population of 9.58 aphids/leaf/plant during the 4 th week of February having a temperature in the range of 30.17 to 18.14 °C, a relative humidity of 73.71% and a rainfall of 0.91 mm and disappeared from the field at the end of March. However, the results of Pavan et al (2019) revealed that the aphid incidence commenced from the 48 th standard week with a pop-https://doi.org/10.17221/31/2022-HORTSCI ulation of 2.50 aphids/3 leaves followed by max.…”

“…Wade et al (2020), from the research, revealed that the whitefly was first noted during the 2 nd SMW on tomatoes along with a peak population level of 7.83 whiteflies per three leaves during the 16 th SMW, while, according to Kachave et al (2020), the whitefly population commenced from the 31 st SMW to the 47 th SMW (30 th of July to 22 th of November) and recorded a maximum and minimum temperature of 34.4 and 18.00 °C, morning and evening relative humidity of 74% and 27%, 6 mm of rainfall and 7.4 hours of sunshine. Mondal et al (2019), from their investigation, found that the incidence of whiteflies initiated in the first week of February with a peak population during the 2 nd week of March with 6.21 whiteflies/leaf/plant having a temperature of 33.96 to 21.21 °C, a relative humidity of 68.43% and a rainfall of 0.10 mm.…”

Evaluation of Life Cycle of Gram Pod Borer Helicoverpa armigera (Hubner) on Vegetable Pea

“…These pests are highly destructive and can significantly reduce crop yield and economic value. They cause severe damage to both the crop and the field, resulting in decreased yield and quality of peas [19][20][21]. The larva, particularly in its second instar stage, poses a significant threat as a single larva can destroy multiple fruits by creating borers.…”