Early blight and late blight are important diseases on solanaceous vegetables.Although the names of the two diseases are only one word difference,some vegetable farmers do not know exactly about early blight and late blight.Some people even think that the two diseases are only happening time different.There are many problems in the prevention and treatment of diseases.Especially in the selection and use of chemical fungicide,blind drug use not only does not play a role in disease prevention,but delays the best prevention and control time,leading to serious diseases.
Early blight mainly affects the stems,leaves,and fruits of vegetables,and is most susceptible to disease at the branches of leaves and stems.At the seedling stage,the base of the stem of the seedlings is dark brown lesions,slightly sunken,and has a ring pattern.The onset of adulthood generally develops from the lower leaves to the upper part.The leaves are infected,the primary brown necrotic small points,and then expanded into a round to nearly round,dark brown,with concentric wheel pattern,the wheel surface has a thorny hair,and some varieties have a yellow-green halo around the lesion.The disease of the fruit begins in the vicinity of the flower buds.It is mostly elliptical to amorphous brown to black lesions,sag,hard,and dense black mold layer in the later stage.The center of the lesion has a concentric pattern.When it is wet,the black mold layer is the main recognition symptom of the disease.
When the late blight occurs,the plants often die in the short term.The disease can occur in the seedling stage and the adult stage.In the seedling stage,the leaves are dark green water-stained lesions,and the lesions spread from the leaves to the main stem,causing the stems to become thin and dark brown,causing the seedlings to wilting or folding.When infected in adulthood,it is often the simultaneous onset of stems,leaves and fruits.The stems becomes dark brown and rot-like.There are water-soaked irregular lesions on the leaves.White mold is found in the disease-health junction on the back of the leaves.The fruit,especially the green fruit,has oil-stained lesions.
