Bioefficacy of Insecticides Against Citrus Butterfly in Kinnow
Citrus (Family: Rutaceae) has originated from tropical and subtropical regions of Southeast Asia, particularly India and China. Northeast India is the native place of many citrus species. Citrus crops due to their unique diversity have greater adaptability for cultivation under tropical and subtropical conditions. India ranks third in the global citrus production after China and Nigeria. The genus citrus includes a large number of species and cultivars, among which, mandarin, sweet orange (mosambi, malta, or satgudi), lime and grapefruit are very popular. In citrus group plants, mandarin is the largest cultivated fruit in India and world due to its high vitamin C and juice content with pleasant aroma and flavor.
In India, mandarin is mostly grown in Maharashtra, Andhra Pradesh, Punjab, and Haryana. In Haryana, the major citrus growing districts are Sirsa, Hisar, Bhiwani, Gurugram, and Fatehabad. Mandarin is grown in the area of 404 thousand hectares with a production of 4964 thousand tonnes in India (National Horticulture Board, 2019). Despite a significant increase in area and production of citrus, its cultivation is under the severe threat of abiotic and biotic stresses, and among them, the insect-pest problem is one of the major constraints. A number of insect-pests attack citrus plants in both the nurseries and orchards, inflicting heavy economic losses.
Among various pests attacking the citrus, the citrus caterpillar [Papilio demoleus Linnaeus (Papilionidae: Lepidoptera)] is a serious pest, which is difficult to kill. Different management strategies are followed to avoid potential threats of a lemon butterfly, which consists of cultural, mechanical, and biological control practices, but these are not easily applicable, labor-intensive, and not very effective in the heavy attack due to various factors. Pesticides provide an easier and quicker option to manage pests. So, new insecticide molecules, particularly which are less hazardous to the environment, need to be evaluated from time to time to identify effective insecticides against pests.
The maximum efficacy was observed in quinalphos 25EC with 52.43 and 85.34 percent reduction of the larval population followed by chlorpyriphos 20EC with 48.06 and 72.67 percent. Quinalphos shows the most effective reduction in larval population over all other insecticides, botanicals, and bio-pesticides tested in reducing the infestation of a citrus butterfly, the reason being its broad-spectrum contact and stomach action. Imidacloprid and thiamethoxam also showed better control due to their systemic action along with unique trans-laminar action. The least reduction of the larval population was found in nimbecidine 0.03%, i.e., 27.17 and 56.01 percent.