Scientists urge use of nematode-free seedlings, soil solarisation and organic amendments; tomato, cucumber, capsicum and brinjal among crops most vulnerable to infestationPAU has advised farmers to use nematode-free seedlings, raise nurseries at clean sites and solarise nursery beds with transparent polythene sheets during May and June. (HT File)The Punjab Agricultural University (PAU) has cautioned vegetable growers about the increasing incidence of root-knot nematodes in net houses and poly houses, warning that the microscopic soil-borne pests can cause substantial losses in yield and crop quality if left unchecked.With protected cultivation becoming increasingly popular in Punjab, crops such as tomato, cucumber, capsicum and brinjal are particularly vulnerable to nematode infestation. While insect-proof structures help reduce damage from major insect pests, continuous cultivation of susceptible crops under the same protected units often encourages the build-up of soil-borne pathogens, especially root-knot nematodes.PAU scientists Sukhjeet Kaur, Anupam Sekhon and Jaspreet Kaur said the pests are microscopic, thread-like worms that attack plant roots and often remain undetected until significant damage has occurred.Commonly referred to as the hidden enemies of plants, they cause characteristic swellings or galls on roots, restricting the plant’s ability to absorb water and nutrients.Affected plants typically show yellowing of leaves, stunted growth, premature leaf fall and wilting during hot afternoons. In severe cases, plants fail to recover even after irrigation and produce fewer, smaller fruits. The scientists noted that cucumber plants usually develop enlarged root galls, while capsicum and brinjal often exhibit finer root swellings.The pest thrives in temperatures between 25°C and 30°C and can complete its life cycle within three to four weeks. A single female nematode can lay up to 500 eggs, allowing populations to increase rapidly under favourable conditions. Sandy soils are especially prone to severe infestations.According to the experts, infected nursery seedlings are one of the main sources of infestation. Small root galls on nursery plants often go unnoticed and can introduce nematodes into healthy fields and protected cultivation units. The pest may also spread through contaminated soil, farm equipment and irrigation water.To manage the problem, PAU has advised farmers to use nematode-free seedlings, raise nurseries at clean sites and solarise nursery beds with transparent polythene sheets during May and June.Green manuring with crops such as sunhemp and marigold, along with soil solarisation in infested structures, can help reduce pest populations.