Main Pests and Diseases of Pineapple
1. Gray speck disease
The spots appear on both sides of the leaves, initially light yellow mung bean-sized spots, which expand when conditions are suitable, and the center becomes black without sinking. The later stage lesions are oval or oblong, often healed, with dark brown edges, yellow halo, gray-white center, and black hair-like dots on the top, that is, the acervulus of the pathogen.
- Strengthen cultivation management, do a good job in orchard irrigation and drainage system, apply fertilizer reasongably, and not apply nitrogen fertilizer excessively; Cut off the diseased leaves at the base and burn them in time, and drain water after rain to prevent moisture.
- At the beginning of the disease, you can choose to use chlorothalonil 50% SC diluted 1000-1500 times, or thiophanate methyl 50% SC diluted 1000-1500 times, difenoconazole 15%+propiconazole 15% EC diluted 2000-3000 times, propiconazole 25% EC diluted 1500-2000 times, or prochloraz 45% EW diluted 2000 times, the water consumption per mu is about 125kg.
2. Leaf spot
It mainly occurs in the middle of the leaves of seedlings and plants. Some lesions are irregular, with light yellow edges and honey yellow in the middle. Diseased leaves are damaged and cannot perform normal photosynthesis and absorb the nutrients needed for plant growth. In severe cases, it leads to premature senescence of leaves and stops growing. The initial lesions are mung bean-sized spots, which gradually expand into oval, light brown, sunken, dark brown raised spots at the edge, and sometimes several spots can merge into large spots.
Same as gray speck disease
3. Heart rot disease
Pineapple heart rot is a soil infectious disease that not only harms seedlings, but also harms adult plants and plants that are about to bear fruit, and causes pineapple roots to rot. It mainly occurs in Fujian, Guangxi, Guangdong and Taiwan provinces in China, and it is common in newly planted pineapple orchards. Once the disease occurs, it will spread rapidly, often causing the whole seedling disease and dead.
- Choose strong seedlings and sow them after a certain drying time; pay special attention to drainage and avoid planting in low-lying and humid places; be careful when weeding in the field to avoid damaging the base of the leaves; find and pull out the diseased plants as early as possible, then replanting,soil changing and lime spraying; fertilize reasonably and do not apply excessive nitrogen fertilizer.
- Seedling treatment, first peel off a few leaves at the base of the seedling, then soak the base of the seedling with 800-1000 times dilution of carbendazim 25% WP for 10-15 minutes, dry it upside down before planting.
- In the early stage of the disease, spray with carbendazim 50% SC 1000-1500 times dilution, or thiophanate methyl 50% SC 750-1000 times dilution, or mancozeb 80% WP 600 times dilution to prevent the spread of the disease.
Pineapple black heart disease is widespread in Guangdong, Hainan, Guangxi and Fujian provinces, which are the main pineapple producing areas in China. The fruit quality can be reduced if the damage is light, and the commodity value will be lost if it is serious.
Dark brown round spots appeared on the surface of the diseased fruits, and then gradually expanded, or merged into dark brown patches by multiple diseased spots, and the internal tissues rotted and gave off wine flavor. In humid environment, many orange-red sticky small particles appear, which is the acervulus of pathogenic bacteria. In severe cases, the whole fruit will rot.
The processed fruits are picked in advance and processed as they are picked to reduce losses; change the fruiting time and arrange more summer and spring fruits in the diseased area; reasonable fertilization: apply sufficient base fertilizer, mainly soil and miscellaneous fertilizers, increase phosphorus and potassium fertilizers, and control the amount of nitrogen fertilizer , The commonly used ratio of nitrogen, phosphorus, and potassium is 3:1:2; Topdressing should be done early to avoid concentrated fertilization in the fruiting period.
5. Black rot
Pineapple black rot (also known as pineapple base rot) occurs in major pineapple producing areas in China, such as Guangdong, Hainan, Guangxi, and Fujian. It is an important disease during fruit ripening and storage. It can also damage seedlings and cause seedling rot. The incidence rate in some producing areas is as high as 30-40%. The pineapple loses its edible value when it rots. It mainly occurs on mature fruits. Water-stained soft spots appear on the damaged fruit surface, which has a clear dividing line with healthy tissues. The disease spots gradually expand to the entire fruit, forming large black patches.
Mainly pulp damage, stem damage and leaf damage.
- Strengthen cultivation management, pay attention to orchard drainage to reduce seedling rot; timely control or pull out diseased plants, timely pick out diseased fruits to avoid contact and infection; during harvesting, transportation and storage, fruits should be handled with care to avoid mechanical damage; Fruit should not be harvested in rainy days, and should not be piled too thick in sunny days. The storage room should be ventilated and dry.
- Seedling treatment, soaking in carbendazim 50% SC 1500 times dilution for 10 minutes and then plant; spraying 1000 times dilution of carbendazim 50% SC or thiophanate methyl 50% SC to protect wound.
- After picking the fruit, use carbendazim 50% SC 1000 times diluent, or thiophanate methyl 50% SC 1000-1250 times dilution to soak the top of the fruit stalk cut for 1 minute, dry it before storage and transportation.
6. Mealybug wilt of pineapple
Mealybug wilt of pineapple (also known as pineapple root rot, pineapple plague) occurs in Hainan, Guangdong, Guangxi, Fujian and Taiwan. The leaves of diseased plants become soft and drooping, the leaves are light green to red, the base rots, and finally the whole plant dies. The upper part of the ground showed that the base leaves turned yellow, reddish, shrunken, lost luster, and the leaf margins curled inward at the beginning of the disease. Later, the tip of the leaf withered, the leaf withered, and the plant stopped growing. As the disease progresses, the root tip rots to part or all of the root rot, and the plant dies.
- Strictly pay attention not to use diseased seedlings; improve the garden environment, strengthen management, use high-border planting, avoid water accumulation and soil erosion in the orchard, and add organic fertilizer to kaolin and clay soil to improve soil aeration and promote the root system grows, and the diseased plants are dug out and burned in time.
- Control pineapple mealybugs in time, soak the seedlings with malathion 57% EC 1000 times dilution or cypermethrin 10% EC 1000 times dilution for 5-10 minutes for disinfection, and then plant them after inverted drying.
- If diseased plants are found, the above-mentioned agents can be sprayed with a mixture of thiophanate methyl 50% SC 400 times dilution and urea 1-2% in time to promote the yellow leaves to turn green.
7. Dysmicoccus brevipes
Both nymphs and female adults can suck the juice of pineapple leaves, stems, fruits and roots. The damaged leaves faded and turned yellow, or even purplish red. In severe cases, the leaves all changed color, softened, and then withered. The damaged roots turn black and brown, and the tissues decay, resulting in weak plant vigor and even the whole plant withered. The skin of the damaged fruit loses its luster and its quality deteriorates; in severe cases, the fruit shrinks and cannot grow. The honey juice secreted by this worm can induce soot disease and spread pineapple blight.
- Select insect-free seedlings.
- Before planting, soak the base of the seedling with malathion 57% EC 1000 times dilution, or cypermethrin 10%EC 1000 times dilution, dimethoate 40% EC 1500-2000 times dilution, or lambda-cyhalothrin 2.5% EC 750-1000 times dilution for 10 minutes.
- For damaged pineapple plants or fields, the above-mentioned agents can be used to drench the plants or irrigate the soil 1 to 2 times or more. Once every 7 to 15 days, the early frequency is high. It can also be sprayed with profenofos 50%EC 2000 times dilution.
8. Tetranychus mites
Use mouthparts to pierce the epidermis of leaves or roots and suck the juice, causing the damaged parts to brown. In severe cases, the leaves shrink, and the fruit withers until the whole plant dies.
- Biological control should avoid excessive fertilization, especially nitrogen fertilizer. When excessive nitrogen fertilizer is applied, plants become more susceptible to spider mites. Timely removal of weeds in the greenhouse and outdoors can reduce the host plants of spider mites. Removing old leaves and residual leaves on plants is also a way to reduce the emergence of spider mites.
- For physical control, it is necessary to remove the damaged plants before the spider mites pupate. This is an important measure to reduce the number of spider mites. In addition, getting rid of females that are hatching eggs is also a way to reduce the damage.
- Chemical control can use insecticides to deal with pests. In fact, spider mite larvae can be well controlled in leaves, so the use of insecticides should be minimized. In order to disturb the habit of spider mites, insecticides can be sprayed in the morning when females lay eggs. Frankliniella occidentalis usually appear together with spider mites. Observe the number of frankliniella occidentalis to see how effective the insecticide is. In addition, neonicotinoid insecticides are effective against species of spider mites that have been found in greenhouses.
9. Trypoxylus dichotomus
Adults bite the pineapple fruit, often a few or more than a dozen of them gather on the fruit and eat the whole fruit. Adults also harm the pineapple tender leaves. From the inside to the outside, they bite on the base mesophyll of the inner layer of the tender leaves, leaving fibers and causing the leaves to die.
- Compost is a hiding place for overwintering larvae and eggs. It should be applied before the end of April and before the emergence of adults. If larvae are found in the compost, they should be treated in time.
- Catch pests. During the peak adult emergence period in mid-May, organize manpower to capture adults.
- Chemical control. Use profenofos 50%EC 1000 times dilution or dimethoate 40% EC 1000 times dilution.
It mainly eats trees by larvae, lives for the longest, and has the most serious damage to the trunk. When the eggs hatch out of the larvae, the first-instar larvae moth into the tree trunk and feed under the bark at first. After the age increases, they penetrate into the xylem and cause damage. Some species only live under the bark and do not moth into the xylem. The larvae move in the trunk, and the shape and length of the worming tunnel vary with species. The larvae eat on the trunk or branches, open to the bark within a certain distance as a vent, and push out excrement and wood chips. The larvae build a wider pupal chamber when they mature, and the ends are blocked with fibers and wood chips, and pupate in it. The pupal stage is about 10-20 days.
Spraying with chemical agents has a significant control effect on juvenile larvae under the phloem that have not yet entered the xylem. Commonly used pesticides are: dimethoate 40%EC, 50% profenofos 40%EC 100 to 200 times dilution; adding a small amount of kerosene, salt or vinegar is better; When smearing the insect gall of twigs, the dilution ratio should be increased appropriately; some pesticides can be mixed. Mainly find wormholes and then inject insecticide.
Crickets are omnivorous and nocturnal pests, which are rampant in loose sandy soil. Crickets have mixed eating habits. When they harm pineapples, adults and nymphs bite into many holes 1 to 2cm in size in the fruit, and the holes flow glue. Fruits that are less than 70% mature, the pulp has a fragrant taste, and more water will cause pathogens to invade and rot, and will attract slugs, Trypoxylus dichotomus and yellow ants, etc., bite from the wound, deepen the wound, and rot expansion, resulting in early ripening of the fruit, low sugar content, low water content, and low flavor. At the same time, it can also cause the invasion of pathogenic bacteria, causing the fruit to rot, making it impossible to eat and process. Before the pineapple fruit matures or after the fruit is picked, the insect bites the mesophyll of several leaves in the inner layer of the seedling's heart, leaving fibers and gradually withering the damaged part.
- Stir-fry fragrant rice bran with methomyl to make poison bait, fry 5 kg of rice bran and 1 kg of cooked sweet potato, add a small amount of pickle juice and add 150g of methomyl 40% WP to make soybean-sized poison bait,put it around the plant to trap the crickets, and scattered where the crickets enter and exit.
- Apply profenofos 50% 500 times dilution once from 5pm to 12pm. If there are many insects, apply once every 7 to 10 days, and apply 2 to 3 times in a row. In addition to killing crickets, it can also kill pests such as Trypoxylus dichotomus, scarabs, and big borers at the same time.
It damages roots, stems, and leaves, often living in groups on them, which can induce pineapple wither and soot disease, which makes the orchard plants grow irregularly, and delay the fruit period.
- Strengthen the management of the orchard, increase the application of decomposed organic fertilizer, rationally irrigate, maintain proper temperature and humidity in the orchard, and pay attention to drainage measures. Improve tree resistance to disease. Combined with pruning, clean the orchard in time to reduce the source of insects.
- Protect and use natural enemies. The main natural enemies are big black ants and small black ants.
- Chemical control methods can refer to "crickets control" or spray termite pesticides on the way the termites pass by to kill the colony.
Adults and nymphs eat leaves. In severe cases, the whole leaves are eaten up, leaving only the veins.
- Rice locusts like to lay their eggs on the ridges, fields, and canals. In areas with severe locust plagues, human resources were organized to shovel and turn over to kill locust eggs, with obvious results.
- Protecting frogs and toads can effectively inhibit the occurrence of this insect.
- Grasp the characteristics of pre-third instar rice locusts swarming on the ridges, fields, and canals to feed on the young leaves of weeds, and surprise and control them. When they enter the 3rd to 4th instars, they are often transferred to the field. When 100 plants have more than 10 insects, spray profenofos 50% EC or lambda cyhalothrin 2.5%EC 2000-3000 times dilution, dimethoate 40% EC 1000 times dilution, cypermethrin 10%2000-3000 times dilution, carbofuran 240g/L 2000- 3000 timesdilution. Both can achieve better control efficiency.
- Plane prevention and control should be used when large areas occur.
14. Amsacta lactinea
Mainly harm cruciferous, beans and green onions and other vegetables. Larvae eat leaves. The first-instar larvae are clustered and harmed and dispersed after the third instar. They can eat the leaves into nicks, and eat up the leaves in severe cases.
- After the vegetables are harvested, plow the soil in time to eradicate weeds.
- Use black light to trap adults.
- Pick them out in time during the eggs peak period or the initial hatching period of the larvae and eliminate them intensively.
- Chemical control is the same as locust control.
15. Black belt weevil
After hatching, the worms first feed on the leaf sheaths, and gradually drill to the center of the upper part of the plant, creating a tunnel with varying vertical and horizontal directions. After maturation, the fibers are crushed in the outer leaf sheath, and glued to form a strong cocoon, and then live in the cocoon and pupate.
- After harvesting, clean up the stubble and eliminate all kinds of insects hidden in it.
- Combined with cleaning the orchard, regularly peel off the leaf sheath with eggs on the outer layer of the pseudostem, and capture the adults.
- Chemical control is the same as crickets
16. Spider mites
Small groups usually spin silk on the back of the leaf and form a net, and inhabit, lay eggs and cause damage under the net. The injured leaves first appear yellow-white to off-white spots on both sides of the main vein of the petiole on the back of the leaf, and then the leaves turn into pale gray. The face turns green. Adult mites, nymphs and eggs can be seen on the back of the leaf turning. When the damage is severe, the leaves will appear scorched and the plants will wilt.
- Eliminate weeds on the edge of the field, maintain field hygiene, timely remove dead branches, old leaves and insect leaves and burn them together;
- Water and fertilize at the right time to maintain proper humidity in the field;
- When sporadic occurrence of spider mites in the field, timely application of pesticides for control. Spraying abermectin 1.8% 1000-1250 times dilution, buprofezin 25% + thiamethoxam 5%SC 4000-6000 times dilution. When spraying, the spray nozzle sprays the back of the leaves obliquely upwards, once every 5-7 days, twice in a row.
- During the growth period, use profenofos 50% 2000 times dilution to control, and it can be used during the flowering period. In order to protect and use natural enemies, the pesticides should be alternated. In the harvest period, matrine spray can be used after the fruit is picked. Predatory mites can be placed in areas where conditions permit. One predator can prey on 300-500 spider mites in its lifetime and also suck harmful mites eggs, which can effectively control the damage of spider mites.
17. Prodenia litura
The first and second instar larvae gnaw on the epidermis and mesophyll of the leaf in groups, leaving only the upper epidermis and leaf veins; Larvae over 3 instars bite the leaves, leaving only the main veins. They are pseudo-dead and sensitive to sunlight. They hide in a dark place during the day when the weather is fine, and come out at night to cause damage. In severe cases, the density of larvae will be high, which will reduce yield and transfer damage.
- Using the chemotaxis and phototaxis of adults, black light lamps, sweet and sour liquid, etc. can be used to trap and kill.
- Natural enemies such as spiders and trichogramma can be used to control the pests.
- Chemical control: Spray pesticides at the early stage of the occurrence of young larvae, and the spraying time is better in the evening. Spray with chlorfenapyr 240g/L 2000-2500 times dilution, or indoxacarb 15% 2000-3000 times dilution, profenofos 50% 2000-3000 times dilution.