Seasonal incidence of aphids and jassids on chilli at Konkan condition

Introduction

Chilli (Capsicum annuum L.; 2n = 2x = 24) belongs to the genus Capsicum and the family Solanaceae. It is an important and widely cultivated spice crop valued for its characteristic pungency, which is primarily attributed to capsaicin, a bioactive compound responsible for its hot and pungent flavour. Chilli has been used by humans since the early stages of agriculture and has become an integral part of cuisines and traditional food systems worldwide. It is cultivated extensively for both domestic consumption and commercial purposes. In addition to its culinary importance, chilli has considerable economic value and serves as a source of bioactive compounds with diverse applications in the food, pharmaceutical, and nutraceutical industries. A total of 57 insects, and mites pests were recorded damaging chilli (Reddy and Puttaswamy, 1984). Aphids and jassids are important sucking pests of chilli, and their infestation can cause substantial yield losses. Yield losses in chilli crops due to sucking pests like aphids and jassids are documented in agricultural research to range between 30 and 50 per cent, and can reach up to 60 to 75 per cent for major sucking pest complexes (Jatav et al., 2021) [4] . Information on the seasonal incidence and the influence of various environmental factors on population fluctuations of chilli pests in the Konkan region is scarce.

Such information is essential for developing effective integrated pest management (IPM) strategies that maintain ecological sustainability and economic viability. Therefore, an attempt was made to study the seasonal incidence of important pests of chilli and to assess the influence of various environmental factors on their population fluctuations.

Materials and Methods

A field experiments was conducted at Vegetable Improvement Scheme, Central Experiment Station, Wakavali running under Dr. Blalsaheb Sawant Konkan Krishi Vidyapeeth, Dapoli to study the seasonal incidence of different pests infesting chilli during Rabi, 2023-24 and Rabi, 2024-25. Konkan Kirti cultivar was planted at spacing of 60 cm x 60 cm in 64.4 m 2 plot area of size of 36 m x 4.8 m in single replication. The crop was kept unsprayed throughout both the seasons to prevent any interventions in surviving pest population. The observations on surviving population of sucking pests viz., aphids and jassids were recorded at each standard meteorological week (SMW) during each cropping season. Ten plants were randomly selected for recording the observations from the experimental plot. The number of nymphs and adults of aphids and jassids were recorded from top, middle and bottom leaves of randomly selected plants. The average pests per three leaves per plant was calculated in each standard meteorological week (SMW). The average aphids and jassids per three leaves per plant of chilli were correlated with meteorological weather parameters in each standard meteorological week (SMW).

Result and Discussion

The data on the aphids and jassids during 2023-24, 2024-25 along with weather parameters of different Standard Meteorological Week (SMW) of are presented in Table 1.

Aphida, Aphis gossypii (Glover)

During 2023-24, the data revealed that the incidence of aphid population was noticed from 50 th SMW (1.10 aphids per 3 leaves per plant) and reached its peak in 8 th SMW (11.70 aphids per 3 leaves per plant) when the prevailing maximum temperature, minimum temperature, morning relative humidity (R.H.-I), evening relative humidity (R.H.-II), wind speed, sunshine hours and evaporation were 34.71℃, 13.09℃, 91.00 per cent, 38.00 per cent, 2.04 kmph, 9.11 hrs and 4.64 mm, respectively. Thereafter, the population of aphids declined gradually and sustained till 15 th SMW (0.70 aphids per 3 leaves per plant). During 2024-25, the data revealed that the incidence of aphid population was noticed from 50 th SMW (1.50 aphids per 3 leaves per plant) and reached its peak in 5 th SMW (13.10 aphids per 3 leaves per plant) when the prevailing maximum temperature, minimum temperature, morning relative humidity (R.H.-I), evening relative humidity (R.H.-II), wind speed, sunshine hours and evaporation were 35.00℃, 13.90℃, 92.00 per cent, 53.00 per cent, 1.30 kmph, 8.10 hrs and 3.40 mm, respectively. Thereafter, the population of aphids declined gradually and sustained till 15 th SMW (0.50 aphids per 3 leaves per plant).

Correlation studies of aphids infesting chilli with weather parameters

The correlation coefficient was worked out between population of aphids and abiotic factors during 2023-24 and 2024-25 and presented in Table 2. During 2023-24, the aphid population showed negative correlation with maximum temperature (r = -0.089), evaporation (r = -0.062), rainfall (r = -0.045) while positive correlation with morning relative humidity (R.H.-I) (r = 0.026), wind speed (r = 0.123). However, aphid population had highly significant and negative correlation with minimum temperature (r = -0.662**), evening relative humidity (R.H.-II) (r = -0.752**) whereas, highly significant and positive correlation with sunshine hours (r = 0.601**). However, during 2024-25, the aphid population showed negative correlation with maximum temperature (r = -0.079), evening relative humidity (R.H.-II) (r = -0.164), wind speed (r = -0.358), evaporation (r = -0.256) while positive correlation with morning relative humidity (R.H.-I) (r = 0.101), sunshine hours (r = 0.358). However, significant negative correlation observed between aphid population and minimum temperature (r = -0.569*).

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