Integrated Control Methods for Pineapple Wilt Disease and Sunscald
Pineapple (scientific name: Ananas comosus), officially and academically known as "fengli" in Taiwan, China and mainland China, is called "ong-lai" (ông-lâi) in Taiwanese Hokkien, "fanli" in the Chaoshan region, "huangli" in Malaysia and Singapore, and is also commonly known as "boluo" in mainland China, Hong Kong, China and Macao, China. Pineapple is a tropical fruit native to the Amazon River basin region of Brazil and Paraguay in South America, and has now spread throughout the entire tropical zone.
Pineapple flesh contains fat, protein, carbohydrates, crude fiber, calcium, phosphorus, iron, carotene, vitamin B1, vitamin B2, vitamin C, niacin and organic acids. Pineapple contains a substance called "bromelain," which can break down protein, dissolve fibrin and blood clots blocking tissues, improve local blood circulation, and eliminate inflammation and edema; the sugars, salts and enzymes contained in pineapple have a diuretic effect, and moderate consumption is beneficial for patients with nephritis and hypertension; pineapple is sweet and neutral in nature, and has functions such as strengthening the stomach and promoting digestion, tonifying the spleen and stopping diarrhea, and clearing the stomach and quenching thirst.
Wilt disease (mealybug wilt disease) is a disease caused by mealybugs damaging pineapple plants and introducing toxins. Affected plants gradually lose leaf color, turning red-yellow with leaf tips shriveling and drooping, leaf edges curling downward and tightly packed, fruit shrinking and drying up, plants noticeably shrinking, and eventually gradually dying.
The control methods are as follows:
1. Select disease-free seedlings for planting, and soak the roots and stems of seedlings for 2 minutes with a mixture of dimethoate and dichlorvos (40% dimethoate 250 g, dichlorvos 250 g, water 50 kg), or 40% dimethoate 800-1000 times dilution, or rosin mixture 6 times dilution.
2. Promptly dig out and remove diseased plants, or drench the base of diseased plants with one of the above chemicals.
3. In lightly affected areas, spray with 500-800 times dilution of thiophanate-methyl plus 1%-2% urea, which can both prevent the spread of this disease and promote yellow leaves to turn green and restore vigor.
Sunscald is a phenomenon in which, during the growth and development of fruit trees, strong direct light causes damage to the fruit surface, affecting the commercial value of the fruit.
Symptoms: After the fruit is scorched, part of the peel shows brown scars, the flesh flavor deteriorates, and there is very little juice. Tissue necrosis occurs, the fruit loses water relatively quickly, and it easily becomes a hollow fruit. This affects the economic development of fruit trees.
Pathogen: It is a physiological disease.
Disease characteristics: During the growth, development and maturation stages of summer and autumn fruit, light is intense, and orchard light intensity reaches 80,000-100,000 lux. Fruit directly exposed to strong light is very easily scorched. This should be given attention.
Control methods
(1) Strengthen cultivation management and scientific pruning, avoiding excessive sparseness.
(2) During the fruit coloring stage, paper bags can be placed over the fruit to reduce damage. At the same time, this can also prevent insect damage.
(3) Several leaves can also be tied together to shade the fruit; when tying leaves, do so appropriately and do not tie too tightly, and pay attention to ventilation.
(4) When pineapple seedlings are sufficient, appropriately remove the crown bud at the top of the fruit, which helps prevent sunscald.
(5) Choose suitable varieties. Pine needles, Dicranopteris fern, etc. can be used to cover the top of the fruit for sun protection, and when necessary, rice straw or other soft weeds can also be used to cover the fruit, but this easily attracts crickets to bite the fruit, so attention must be paid to preventing crickets.