Guava (Psidium guajava Linn.) Commonly known as bale, plucked guava seeds, napa, etc., belongs to the myrtle family guava is an evergreen small tree or shrub, native to tropical countries in the Americas, and is now mainly produced in India, Brazil, Mexico and South China in China. Guava was introduced to China in the 1st century, and is cultivated more in Taiwan, China, and in recent years, Guangdong and other southern regions have also developed to a certain extent. In 2003, the Beijing Agricultural Technology Extension Station introduced guava into the north for cultivation and successfully cultivated it in the solar greenhouse. In 2007, the agricultural parks in Daxingtongzhou and Changping Districts of Beijing began to promote planting, which has stable adaptability, good ornamental value and high economic benefits.
1. Varieties
Guava is widely distributed in the world, and the varieties are very rich. In China, the main varieties in Guangdong are early maturing white, palace pink, full red, birth red, large leaf red, July red, Thai fruit; The main varieties in Fujian are Taiwanese guava, Luzon guava, persimmon guava, Baixiu guava, October guava, and guava of the four seasons; The main varieties in Taiwan are Dongshan Yueba, Pear Boy, Rimao Yueba, Dongba, Pearl, crystal; The main varieties in Yunnan are red heart guava, local calamus, and large-fruit guava; Guangxi has Vietnamese guava and large fruit guava.
Guava grafting is made from this rootstock, and local guava, strawberry guava, Brazilian guava, Costa guava, huangsara guava, etc. can be used as rootstocks.
Strawberry guava: hexagonal, purple or yellow fruit, for fresh food or processed juice, jelly, etc., more hardy, can be used as guava rootstock.
Brazilian guava: tetraploid, small fruit, abundant, better quality, more hardy.
Costa guava: hexagonal, round fruit, thin flesh, sour taste, no aroma, few seeds, high pectin content of mature fruit, resistant to nematodes and withering, can be used as guava rootstock.
Yellow Salo Guava: Small fruit, pale yellow, slightly sour, slightly strawberry aroma. Underripe fruit can be made of high-quality jelly, seedlings have poor cold tolerance, are susceptible to root nematodes, and can be used as guava rootstock.
2. Planting conditions
Guava has wide adaptability and is not strict on soil requirements, and can be planted in the range of soil pH of 4.5 to 8.0, but the best is 5.5 to 6.5. Guava grows fastest at a temperature of 23 to 28 °C, and the lowest monthly average temperature of 16 °C is conducive to its growth; The minimum temperature that the tree can tolerate is 0 °C, so the unheated solar greenhouse in the Beijing area can be planted normally, but it needs to be heated in the early market.
The garden is suitable for choosing a greenhouse with no frost in winter and moderate high temperature in summer, sitting north and facing south, with plenty of sunshine and convenient drainage and irrigation. Guava has a high survival rate from March to May, while nutrient bag seedlings can be planted all year round. The row spacing of the plants is 2 m×3 m. At the beginning of planting, attention should be paid to irrigation, shading and maintaining a relative temperature so that the roots can grow smoothly.
Solar greenhouses with no thermal insulation facilities in the north must ensure that the minimum temperature at night is stable above 15 ° C before they can be planted. The suburbs of Beijing are generally in mid-to-late April, when the temperature is suitable and gradually rises, which is conducive to planting in the same year, flowering and fruiting in the same year, and economic benefits can be achieved in the same year.
3. Propagation methods
Guava is propagated by sowing seeds and cuttings.
1. Sowing
When the seeds are ripe, they are sown immediately, sown or striped, and the seedlings emerge after 2 to 4 weeks. Transplant once the seedlings are 3 to 4 inches tall, and if they grow well, they can be colonized one year after sowing.
2. Seedlings
Guava can be bred using solid raw, cuttings, and circle branches (aerial striping and grafting). Since roots can occur in the root system, seedlings can also be bred by the plant splitting method. However, there is variability in real breeding, and it is best to use a nutrient bag.
(1) Grafting seedlings generally use this anvil. When the diameter of the seedling reaches 0.7 cm, it can be grafted. It can be used by budding or grafting. The time is suitable for winter and spring. Scion should not be too old or too tender, and it is advisable to take the branches that have just peeled off. Remove the leaves 10 to 15 days before scion collection and cut them when the buds are about to germinate, which is the best effect. Rootstocks are thick and accumulate more nutrients, which is conducive to grafting into life. Generally, the buds are unbound 1 month after the buds are harvested, and the anvils are cut after the buds are healed and alive, which promotes the growth of scion germination, and can be planted in the nursery after 1 year.
(2) Circle branch seedlings are selected from 2 to 3 years old branches with a diameter of 1.2 to 1.5 cm, and the ring peel is 40 to 60 cm from the top of the branches, and the ring peel is 2 to 3 cm wide, and the rooting medium is wrapped. Before wrapping the rooting medium, the ring peeling with indole butyric acid (IBA) aqueous solution or lanolin can promote early root onset, the amount of roots is large, and the survival rate is also high. After 2 months, the new roots were sawn off the mother plant when they were growing intensively. Plant after the second shoot and turn green.
(3) Cuttings seedlings cut 2-3 year old branches with stem thickness of 1.2 to 1.5 cm, length 15 cm, and cut cuttings in February to April. Treating the base of the cuttings with 0.2% indole butyric acid can promote hair roots, and adding 2% sucrose is better. It can also be treated with 0.2% naphthaleneacetic acid (NAA) with leaf cuttings for better results under spray conditions. After treatment, it was cultivated in a 28~32 °C insertion bed, and the root hair was fast and good.
Fourth, cultivation management
1. Colonization
Early guava cultivars and poor soils can be planted with row spacing of 4 m×4 m; Medium and late maturing varieties and fertile soils can be planted with row spacing of 6 m×4 m or 5 m×5 m.
2. Fertilizer water management
In the first year of colonization, each plant was subjected to 2 kg of ternary compound fertilizer (nitrogen, phosphorus and potassium content of 15%), 1 kg of bean bran (or organic fertilizer such as chicken manure and pig manure with equivalent fertilizer), 0.2 kg of potassium sulfate, and 0.5 kg of shell ash; In the second year of colonization, the amount of fertilizer applied in the previous year is increased by 1 times; In the third year of colonization, the amount of fertilizer is no longer increased, or the amount of fertilizer can be increased according to the tree potential and yield.
Fertilization is applied once a year before flowers and after fruit picking, mainly organic fertilizers such as poultry and livestock manure. Apply 25 to 30 kg per plant each time, and add compound fertilizer 0.5 to 1 kg. After flowering to the fruit development stage, apply rotten and ripe manure once every half a month.
Due to the large growth and high yield of guava, there is often a deficiency in production, especially the trace elements zinc and boron, so it is necessary to supplement trace elements through foliar spray fertilizer. In case of zinc deficiency, it can be sprayed foliar with 0.2% zinc sulfate or zinc oxide; When boron is deficient, the foliar surface can be sprayed with 1000 times the aqueous solution of borax, and then sprayed again after 20 days.
After colonization, the soil is required to be moist, watered once in 3 to 5 days, watered once in 5 to 7 days after a month, and watered once in 10 days after 2 months. The amount of watering each time should not be too large, so as not to excessively reduce the temperature and affect the ventilation of the root system.
Pay attention to drainage in the rainy season, pay attention to irrigation in the dry season, store shallow water in the deep ditch of the orchard in winter, and cover the mulch film insulation after winter.
3. Flower and fruit management and pruning
(1) Thinning flowers and fruitless guava flowers are large, and there are many hanging fruits. In order to improve the quality of the fruit, in the flowering and fruit stage to carry out flower thinning, timely removal of double flowers, three flowers and stunted flowers, retain robust single flowers, and to properly thin the fruit, usually each branch to leave 1 to 3 fruits can be.
(2) Branch pruning will cut off dense branches, fine and weak branches, and aging branches, leaving the well-developed and nutrient-rich fruiting mother branches. Pruning is mastered at 35% to 65% of the total canopy, and the next time the other branches are pruned, the cycle of pruning is alternate.
(3) When the diameter of the fruit reaches 2 to 3 cm, after the malnourished and large amount of fruit is removed again, a uniform pollution-free insecticide and fungicide spray is carried out on the tree body. After 2 to 3 days, after the dew is steamed in the morning, the bagging begins, only the fruit grains are put into the bag, the leaves are left outside, and the mouth of the bag is tightened, leaving a gap to facilitate ventilation and moisture discharge.
Fifth, the prevention and control of diseases and insect pests
1. Major diseases and their prevention and control
(1) Green blight guava is infected by green blight bacteria, the whole plant growth stops, the old leaves fall off first, and although the upper leaves stay on the branches of the plant, the leaves turn yellowish white, or pale yellowish green, and finally gradually infect the whole plant to die. The control method is to first remove the soil of the plants in the affected area, move them into the new soil, and then plant new seedlings. In addition, when guava wants to be planted, you should pay attention to the early crops in the garden, avoid planting directly after crops that are susceptible to blight such as peppers, eggplants, tomatoes, etc., or intercropping such crops in the garden to reduce the occurrence of diseases.
(2) Anthrax first appears on the surface of the fruit with softened water-stained spots, the spots fade or appear brown, the center of the spots is black, and it will be slightly inwardly sunken; Punctate pink mucus is often seen on black spots, which are conidia and conidia of anthrax bacteria. Conidia often move to new branches with washdowns such as rainwater, and re-infect. Fruits infected with anthrax will appear pink, lilac and other colors in the central part of the patient, and the external tissues of the patient will fade into water stains. Commonly available control agents are 50% imidamine (Shi Baoke), 50% dentate, 40% sterilized Dan, 50% tolbuzin wettable powder, etc., which are applied after rain or pruned; In addition, sterilization and disinfection before bagging also needs to be applied, and the concentration of the agent is adhered to before starting bagging, and then bagging is applied to reduce the harm.
(3) Canker disease mainly harms the trunk, branches and fruits of guava trees. Branch damage is manifested by bark ulceration and wrinkles. The bark of the initial diseased part is pale brown, and the outer layers on both sides of the diseased part are brown or dark brown. With the up and down expansion of the disease marks, the symptoms of stem ulceration and cracking are aggravated, and the bark is split along the disease marks, and in severe cases, it is circumnavigated around the trunk for 1 week, causing the whole branch and the whole plant to die. The fruit is initially damaged with light brown fruit rot spots, and later becomes dark brown to black, the skin is wrinkled, and finally the whole fruit is black and rotten. The disease has a long incubation time and can occur in the field all year round. Prevention and control methods: First, combine pruning to completely remove the fine branches that have been diseased, and then apply 1 to 2 times 50% debacterial special wettable powder 50 times liquid or 1 baumedo stone sulfur compound; The second is to strengthen orchard management, reduce the wounds caused by other diseases and insect pests, and apply fertilizer reasonably to make fruit trees grow robustly and improve disease resistance.
(4) Root-knot nematode disease Guava is seriously noduled in the root system after being damaged, and it also has tumors on the branches and roots, and the root bark of some of the branches is necrotic and rotten, and a large number of male nematodes can be detected on the affected roots. The control methods are to pay attention to plant quarantine, cultivate disease-free seedlings, and implement comprehensive control measures based on pesticide control. Pesticide control, soaking the soil and roots of the nutrient bag with dichlorvos or insecticidal double 500 times liquid; Use 1.8% efudine emulsion 170g/50kg of water to pour in the cultivated layer of diseased trees 15 to 20cm deep around the main trunk, and the insecticidal effect is better; Or with octyl thion granules, groove or hole application, every 667m2 dosage of 6 ~ 7 kg, the efficacy period of up to 2 ~ 3 months.
2. Major insect pests and their control
Peach borer moth can be controlled with 2.5% kung fu emulsion 2000 times liquid. Aphids, whiteflies, etc. are controlled with 25% chlorpyrifolide 1000 times liquid or 40% rapid culling 1000 times liquid.
6. Harvesting
Guava has the best flavor when fully ripe, and is generally harvested when it is fully ripe for fresh consumption. Therefore, it is necessary to master the standards of mature harvesting. The unripe fruit of guava is green, coarser and less lustrous; The ripe fruit is plump, pale greenish yellowish in color, shiny, colored varieties show an inherently beautiful color, and the flesh is crunchy. Due to the successive flowering periods and the inconsistent ripening period of the fruit, they should be harvested with ripening. During the period of large-scale ripening of guava, it should be harvested once a day, and it is best to harvest in the early morning, when the temperature is low, the light is weak, the fruit flavor can be better maintained, the causal shape is larger, and the fruit temperature is low.
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