Diseases and Pests of Black Nightshade: Control Methods and Key Technical Points

Black nightshade (Solanum nigrum) is a plant with relatively strong resistance to pathogens, so when problems occur they are mostly caused by pests and diseases transmitted by insects, while diseases themselves are less common. People commonly use it as a medicinal herb, and it has a good effect on invigorating the blood and resolving blood stasis. So what diseases and pests does black nightshade generally develop? Qinnongwang takes you through them.

1. Stem base rot

This is easily caused by incomplete disinfection of the planting soil or by continuous cropping over many years. First the plant shows wilting, wilting from the roots upward, and finally the leaves begin to rot, rotting from the top downward. After this condition appears, it is best not to plant there for the time being, or to practice crop rotation, and wait until the virus content in the soil is lower before planting. The common solution is to spray chemicals for disinfection, spraying agents such as Bacillus subtilis and hymexazol onto the planting area once a week for one month.

2. Aphids

This is a parasite that black nightshade is relatively prone to infection by; it mostly appears on the surface and is easily spotted with the naked eye. The symptoms are pale yellow egg-like objects on the leaf surface, densely packed in a sheet, with some showing a spotted distribution. Then the leaves slowly curl into a cylindrical shape and turn yellow. In daily care, all kinds of residue in the field soil need to be removed to reduce pathogens. When this problem appears, the infected leaves need to be picked off, and the plant needs to be sprayed with 0.5 matrine aqueous solution diluted 600-1000 times, and the surrounding plants also need to be sprayed.

3. Spider mites

This is a pest that easily causes black nightshade to drop its leaves, and it generally attaches to the underside of the leaves. The symptoms are that the leaf surface clearly tends to wither, then white spots appear on the leaves, and in some places holes also appear. When the white spots cover the entire leaf, the leaf falls off directly; if you turn it over at this point you will find the underside is already entirely covered with mites. It is recommended to spray the plant with 20% fenpropathrin emulsifiable concentrate diluted 2000 times.

4. Lady beetles

This is the pest most harmful to black nightshade; it directly treats the leaves as food, and in severe cases will also eat the branches and stems. The symptoms are that where the lady beetles attach, the leaves become incomplete or develop holes, and some leave the leaf epidermis on the sun-facing side while eating away the other parts. At this point, chemicals must be sprayed promptly; 40% chlorpyrifos emulsifiable concentrate diluted 2000 times can be used.

Treatment for the above problems must be timely, and it is best to take residues away and burn them to avoid infecting other plants. Daily clearing of the farmland must also be thorough, as many pests and diseases are caused by residues. So special attention must be paid to this aspect.