Palampur: Alligator weed threatens kharif crops

Agricultural scientists from Chaudhary Sarwan Kumar Himachal Pradesh Agricultural University, Palampur, have raised a red flag over the rapid spread of Alternanthera philoxeroides, commonly known as alligator weed. Locally referred to as “Nali Ghas” or “Dodhu Ghas,” this invasive plant is wreaking havoc on both aquatic and terrestrial ecosystems in Himachal Pradesh.

This kharif season, the weed has emerged as a major threat, particularly in paddy fields, but its presence has also been reported in maize, soybean and vegetable crops. According to experts, alligator weed’s aggressive vegetative growth, short juvenile period, and high adaptability to varied environmental conditions enable it to spread rapidly. It competes fiercely with native vegetation and cultivated crops for nutrients, water, sunlight and space. Its allelopathic properties further suppress crop growth, resulting in reduced yields.

To tackle this growing menace, the university has proposed crop-specific control measures. For rice and maize fields, selective herbicides such as 2,4-D ethyl ester or sodium salt @ 1000 g/ha, metsulfuron methyl @ 4–6 g/ha, and carfentrazone @ 25 g/ha have been recommended. In non-cropped or fallow areas, glyphosate @ 1000 g/ha has proven effective in controlling the weed.

Vice-Chancellor Dr Naveen Kumar stressed the importance of early and timely intervention. “Farmers must adopt these management strategies to protect yields and curb the weed’s spread,” he said, urging cultivators to consult Krishi Vigyan Kendras (KVKs) or agriculture extension officers for proper application methods.

The university has underscored the need for coordinated efforts to check the weed’s advance and safeguard the region’s agricultural productivity.