What is pineapple black heart disease? How to prevent and cure

What is pineapple black heart disease? How to prevent and cure? Please point out that the black heart disease of pineapple is one of the main diseases of pineapple, which mainly harms the fruit, affects the fruit quality in light cases, and loses the commercial value in serious cases. Symptoms: the disease mainly harms mature fruits. There are two symptoms: one is that the small fruit turns brown or forms a black spot, and gradually cork, which hardens the pulp, which is the main feature different from black rot; the other is that the pathogen infects part of the carpels, and when the diseased fruit is cut open, the pomelo part of the near fruit becomes dark and water-stained, and then turns black. The appearance of the infected fruit is the same as that of the normal fruit, but the diseased fruit can be distinguished according to the different sounds when knocking the fruit. Pathogen: the pathogen of the disease is not very clear. Some people think that it is a kind of bacteria that causes the small fruit to blacken, and the pathogen that causes the blackening of grapefruit is a kind of fungus. However, most scholars believe that the disease is a physiological disorder caused by low temperature. Conditions of onset: low temperature and variable temperature are the dominant factors in the prevalence of the disease, and the climate with great changes in temperature and temperature below 25 ℃ is the most likely to cause black heart disease. There is generally no black heart disease or less black heart disease in summer fruit, and the incidence of winter fruit is the highest. There are obvious differences in resistance among pineapple varieties. according to the study, the Philippine (Bali) species belong to the highly susceptible type, the unprickly caine species belong to the susceptible type, and the "Nanyuan No. 5" being popularized in Guangxi is the moderately resistant type. The maturity of the harvest also has a great impact, the higher the maturity, the more serious the disease. In addition, partial or late application of nitrogen fertilizer, excessive use of "920" and other plant hormone pesticides will also aggravate the disease. Prevention and control methods: 1. Select disease-resistant varieties. Among the current cultivated varieties, except "Nanyuan No. 5", none of the other varieties are resistant to disease. two。 Cultivate and prevent diseases. ① rational fertilization: apply sufficient base fertilizer, mainly soil fertilizer, increase phosphorus and potassium fertilizer, control the amount of nitrogen fertilizer, and the ratio of nitrogen, phosphorus and potassium is 3 ∶ 1 ∶ 2. Topdressing should be early to avoid concentrated application in the fruiting period. ② strictly controls the concentration and times of "920" and naphthylacetic acid. It is usually better to mix 75 units of "920" with 200 units of naphthylacetic acid, and attention should be paid to the period of use: from the florescence, dripping or spraying every 10 to 15 days, only three times in a fruit season. ③ calcium supplement also has a certain disease-resistant effect during the fruit growth period, and attention should be paid to controlling the spraying concentration of calcium chloride less than 3% to avoid burning the fruit. 3. Timely harvesting and processing. Autumn and winter fruits should be harvested when the maturity is about 60-50%, and canned fruits should be processed within 2-5 days after harvest. Do not pick fruit on rainy days and when the dew is not dry. The long-distance transportation is transported by refrigerated truck and the constant temperature is kept at 7: 8-good. Click to get more pineapple planting techniques click to get more fruit planting techniques