Evaluation of medicinal plant-based formulations for growth, yield and pest management in chilli (Capsicum annuum Linn.)

Abstract

Pest management is one of the important components of crop management to mitigate economic losses of agricultural crops and commodities. The harmful effects of chemical pesticides on environment and health concern have caused a shift to adapt various ecofriendly ways of pest management. Therefore, botanical pesticides are gaining popularity because they are safe to use on crops produced for human consumption and recently there is a lucrative market among consumers willing to pay more for organically produced food. This positive trend has encouraged the research field to focus more on ecofriendly and effective pest management strategies. A study entitled “Evaluation of medicinal plant-based formulations for growth, yield and pest management in Chilli (Capsicum annuum Linn.)” was carried out at the Department of Plantation Crops and Spices, College of Agriculture, Vellanikkara during the period from October 2020 to May 2021 with Chilli variety Anugraha as the test crop. Three medicinal plant based trial products (P1, P2, and P3) and their combinations (P4, P5 and P6), developed and screened at Aromatic and Medicinal Plants Research Station (AMPRS), Odakkali were utilized for the study. P1 was developed from Vayambu (Acorus calamus), P2 from Manja Koova (Curcuma zedoaria), P3 from Erukku (Calotropis gigantea), P4 from Acorus calamus and Curcuma zedoaria, P5 from Curcuma zedoaria and Calotropis gigantea and P6 from Acorus calamus and Calotropis gigantea. Solid soap formulations of these three and their combination were evaluated at one and two per cent concentrations at ten days intervals along with an absolute control (T13- 1% soap solution without any botanicals) and positive control (T14-1% Neem garlic extract). The growth parameters like plant height (cm), leaf length (cm), breadth (cm),and days to 50 per cent flowering and fruiting, yield characters like fruit length (cm) and breadth (cm), fruit weight (g), number of fruits and fresh fruit yield per plant and qualitative characters like Vitamin C (mg 100g-1 ) and oleoresin content (%) were recorded. Statistical comparison of morphological and qualitative parameters under various treatments was done through one-way analysis of variance (ANOVA) using KAU GRAPES software. Effect of spraying the liquid formulations of medicinal plant based products and their combinations against sucking pests like thrips, whitefly and aphids during the experimental period (December, 2020 to May, 2021) were studied. Population density of sucking pests viz. thrips, white fly and aphids were recorded. Data on mean population of sucking pests were tested by analysis of covariance (ANOCOVA) using R studio software, taking population counts prior to the treatments application as covariate. The result obtained was subjected to Duncan’s Multiple Range Test (DMRT) and treatments were analysed. The plant height showed an increasing trend from one month after transplanting to five month after transplanting. The increment in plant height was reduced from three months onwards after attaining the reproductive stage. The maximum cumulative plant height of 61.05 cm was observed in T3 (Calotropis gigantea at 1%) among the treatments.The maximum cumulative leaf length of 5.82 cm was observed in T2 (Curcuma zedoariaat 1%). The maximum cumulative leaf breadth of 2.87cm was observed in T14 (Pest management as per Organic POP). Days to 50 per cent flowering for different treatments varied from 42.66 to 47.66 days. The minimum days to 50 per cent flowering recorded in T5- Curcuma zedoaria at 2 per cent and T6- Calotropis gigantea at 2 per cent. Days to 50 per cent fruiting for different treatments varied from 55 to 62.66 days. Treatment T9- Curcuma zedoaria and Calotropis gigantea at 1 per cent recorded minimum days to 50 per cent fruiting (55 days). Fruit length of chilli variety Anugraha under different treatments varied from 6.13 cm to 6.80cm. The maximum fruit length of 6.8 cm was recorded in T6 (Calotropis gigantea at 2%). Fruit breadth (cm) varied from 2.16 to 2.76 cm. The maximum fruit breadth of 2.76 cm was recorded in T5- Curcuma zedoaria at 2 per cent. Per fruit weight ranged from 1.22 to 1.63 g. The maximum per frit weight of 1.63 g was recorded in T3 (Calotropis gigantea at 1%).The number of fruits per plant ranged from 35.15 to 104.95 and the maximum number of fruits per plant (104.95) was recorded in T6- Calotropis gigantea at 2 per cent. The fresh fruit yield per plant ranged from 54.95 to 121.90 g. Treatment T6 (Calotropis gigantea at 2%) recorded the maximum fresh fruit yield per plant. Factors which influence the yield of the crop like maximum plant height, earliness (minimum days to 50 per cent flowering and fruiting), maximum fruit length, maximum number of fruits per plant were recorded in T6 (Calotropis gigantea at 2%). There was no significant difference for the qualitative characters like Vitamin C (mg 100g-1 ) and oleoresin content (%) with respect to the application of the medicinal plant based formulations. Efficacy of medicinal plant based formulations was studied against various sucking pests during the experimental period. Calotropis gigantea based pesticidal soap formulation showed comparatively good results against thrips population in chilli variety Anugraha under different treatments. Minimum population of whitefly was observed in the treatment T4- Acorus calamus at 2 per cent among various treatments. Acorus calamus based formulation also showed good results with lower pest load against aphids. In general, over all disease incidence in the treatment plot was negligible during the experimental period and Calotropis and Acorus based formulations were showed comparatively good performance in the aspects of growth, yield and pest management in chilli variety Anugraha.