Common diseases of lentil and their control

Regarding the prevention and control of lentil diseases, I think it is an issue that the farming people are very concerned about. Let’s learn about it together.

Lentils

White lentil, scientific name Dolichos lablab L., is an annual creeping herb of Leguminosae. Its flowers and pedicels are used as medicine and are called "Southern Bean Flower". It has the effects of harmonizing the stomach and removing dampness, strengthening the spleen, and stopping diarrhea. It is distributed in South China, East China and North China.

Symptoms Anthracnose of white lentil causes cotyledon disease in the seedling stage, and damages true leaves, stems, pods and beans in the mature stage. When the cotyledons are infected, the cotyledons are infected before they are unfolded after germination. Light brown to reddish brown sunken spots appear on the edges of the cotyledons. When the humidity is high, pink sticky substances grow on them, which are the conidiophores and conidia of the pathogen. Severe cotyledons dry up and die; in the mature stage, the true leaves are infected with small dark brown spots on the leaves at first, and then the spots expand along the veins into small polygonal strips, reddish brown to black; the petioles and stems are infected with spots similar to those on the cotyledons; the immature pods are infected with round to oblong sunken spots, 0.5-1cm in size, dark brown to black in the center, and light brown or brown-red on the edges. After the white lentils mature, the spots gradually become lighter in color, with slightly raised edges and sunken in the center; the spots on the seeds are irregular, yellow-brown to dark brown. The edges of anthracnose on pods and leaves of lentils spread radially, and the presence of spreading edges is different from other anthracnose. When the humidity is high, the diseased part secretes orange-red secretions, which are the conidiophores and conidia of the pathogen.

Lentil disease control

The pathogen colletotrichum lindemuthianum (Sacc. et Magn.) Bri. et Cav. is called bean thorn disc spore, belonging to the subdivision of Ascomycota. For morphological characteristics, please refer to the book "Fava bean anthracnose". The sexual state Glomerella lindemuthianum (Sacc. et Magn.) Shear et Wood is called kidney bean small cluster shell, belonging to the subdivision of Ascomycota. The ascus is spherical to pear-shaped, with a diameter of 250-380μm; the ascus is 70×7-8 (μm); the ascospore is cylindrical, with a size of 15-22×4-6 (μm). The asexual conidial disk is 50-100μm in diameter, with bristles around it, and a size of 30-60×3-5 (μm); the conidia are elliptical, with a size of 15-19×3-5 (μm). It harms lentils, kidney beans, soybeans, mung beans, broad beans, peas, cowpeas, etc. In addition, there are reports that C. truncatum (Schw.) Andr. et Moore, also known as flat-headed spiny disc spore, can also cause the disease.

Transmission routes and conditions for disease occurrence The pathogen mainly lurks under the seed coat as hyphae or overwinters on the ground as hyphae with diseased residues. The following year, sowing diseased seeds causes the cotyledons or tender stems of seedlings to become infected, and the conidia produced by the diseased parts spread through insects and wind and rain for re-infection. When the bean pods are infected, the pathogen enters the seed coat through the pod shell, causing the seeds to be infected and become the source of infection at the beginning of the next year. Temperatures of 17-20℃ and relative humidity of 100% are conducive to the disease. In production, warm, humid, rainy, dewy, foggy, low-lying terrain, excessive density, and heavy soil will cause severe disease.

Prevention and control methods (1) Select disease-resistant varieties and keep disease-free seeds. Collect seeds from disease-free pods and sterilize them if necessary. Soak seeds in 45℃ warm water for 10 minutes or 40% formalin 200 times diluted for 30 minutes, then rinse, dry and sow. You can also mix seeds with 0.3% of the seed weight of 50% thiram powder or 0.2% of 50% tetrachloranil, 0.2% of 50% carbendazim wettable powder. (2) Remove diseased residues in time after harvest to reduce the source of bacteria. (3) It is recommended to apply compost fermented with Japanese enzyme bacteria or fully decomposed organic fertilizer. Severely diseased fields should implement 2-3 years of crop rotation. Sow early and at an appropriate depth. Pay attention to removing diseased seedlings when thinning and strengthen fertilizer and water management. (4) For old poles, spray with 1000 times diluted 50% mancozeb aqueous solution for sterilization before inserting the poles. (5) At the early stage of the disease, spray 80% anthrax fumei wettable powder 900 times liquid or 50% benomyl wettable powder 1500 times liquid, 50% carbendazim wettable powder 600 times liquid, 80% xinwansheng wettable powder 500 times liquid, 30% basic copper sulfate suspension 400 times liquid, 1:1:240 times Bordeaux mixture once every 7-10 days, and control 2-3 times in succession. Stop using the medicine 3 days before harvest.