What are the control methods for root-knot nematodes? Read this article to understand
Root-knot nematode is a highly specialized omnivorous plant pathogenic nematode that mainly damages the roots of various vegetables. It is necessary to strictly implement the plant protection policy of prevention first and integrated control, focusing on agricultural and physical control measures, combined with chemical and biological control, in order to effectively prevent its damage. Let us take a look at the control methods for root-knot nematodes below!
Damage characteristics of root-knot nematodes
Root-knot nematodes mainly damage the roots of various vegetables, showing an increase in lateral roots and fibrous roots compared to normal, and forming spherical or conical white root galls of varying sizes on the fibrous roots of young roots, some appearing bead-like. The aboveground part of the affected plants grows short and slow, with abnormal leaf color, few fruits, low yield, and may even cause premature death of the plant.
Epidemiology of root-knot nematodes
The life cycle of root-knot nematodes goes through three stages: egg, larva, and adult. Under suitable conditions, the egg divides into about 20 cells after 2 days, then enters the blastula stage, and after another 2 days, enters the gastrula stage on days 4 to 5. After another 4 to 5 days, a stylet first appears, forming a first-stage larva, and after a resting period and the first molt, it hatches from the shell as a second-stage larva. The second-stage larva is the only effective stage for root-knot nematodes to infect and damage plants. The second-stage larva enters through the plant root tip, and after two molts develops into an adult. The male adult returns to the soil, and the female adult lays eggs to reproduce. Most root-knot nematodes only reproduce by parthenogenesis. They mainly overwinter in the soil as eggs, egg masses, or second-stage larvae with diseased residues. When the temperature reaches above 10°C, the eggs can hatch into larvae.
Control methods for root-knot nematodes
1. Root-knot nematodes are mainly distributed in the surface soil at 3 to 10 cm, and are rarely present in soil below 15 cm. They can be killed at 55°C in 8 to 10 minutes. Taking advantage of this characteristic, methods such as burning, flooding, and high-temperature chamber sealing can be used to eliminate them when changing crops in summer.
2. Implement crop rotation and intercropping with Welsh onion and garlic. Every 2 years, plant one crop of Welsh onion or garlic, or intercrop garlic sprouts between the rows of the main vegetable crops. After the garlic sprouts grow, use the harvest method of cutting chives, leaving the roots to regrow, and let them remain for a long time. This can significantly reduce the damage of root-knot nematodes, also reduce the occurrence and development of other diseases, and increase greenhouse income.
3. Apply Haishengsu three-element organic fertilizer, phosphorus and potassium fertilizers, and trace element fertilizers to the soil, and continuously spray the plants with “Haishengsu foliar fertilizer” to ensure the plants are robust and vigorous. In addition, the oligochitosan specially added to the Haishengsu series fertilizers has an inhibitory effect on nematodes and can effectively improve their stress resistance to root-knot nematodes.
4. When transplanting seedlings, irrigate heavily. Apply one bottle each of Changge 1# + 2# per mu, with a duration of more than 4 months; or apply 16 bags of Fuqiduo per mu, with a duration of 2 months; or use 2 to 3 bottles of 2% abamectin 1 kg per mu, with a duration of one month; or apply 10% Limanku granules in holes, 25000 grams per mu, to kill residual nematode sources in the soil.