Guava Pests, Diseases, and Control, Guava Plant Care

Introduction to Guava pests, diseases, and their control

The Guava tree is hardy, aggressive, and a perennial tree that has recently become a cultivated crop of subtropical regions. Guava is scientifically Psidium guajava and belongs to the family Myrtaceae. Guava trees are damaged by the citrus flat mite. Guava is an evergreen shrub or small tree grown for its edible fruits. Guava has a slender trunk with smooth green to red-brown color bark. The trunk can be branched at the base and the branches droop low to the ground. The Guava fruit is oval in shape and green to yellow in color. The flesh inside can be white, yellow, pink, or red in color and also contains numerous yellowish seeds. Guava can reach grow to 10 m (33 ft) in height and lives for about 40 years.

A guide to Guava plant pests, diseases, and their control

Guava is considered to be a hardy fruit crop and it is not very choosy for soil. Guava trees can grow well in slightly alkaline and poor soil. It is an important fruit of tropical and subtropical areas of the world and it is called the poor man’s fruit. Guava fruit contains maximum vitamin C and it contains antioxidant factors and can control systolic blood pressure. It is a good source of roughage and also helps in the removal of constipation. In India Guava is cultivated throughout except higher hills. It is mainly grown in the tropics and will tolerate temperatures between 15 and 45°C. Guava will grow between 23 and 28°C but established trees can tolerate short periods at -3 to -2°C although temperatures below 15°C (60°F) can cause the tree to cease producing fruit. Guava is also amenable to a wide range of soils and will grow in both sandy and rocky soils in addition to loams, preferring a pH level of 4.5–7 but tolerating alkaline soil to pH 8.5.

Guavas are more resistant to drought than most tropical fruits and withstand long periods of dry weather by ceasing vegetative growth until conditions improve. Guavas that are grown for fresh fruit are vegetatively propagated by air layering or budding. Planting seeds Guava seeds are started in nursery beds or pots before being transplanted in the garden. Guava planting is done during the rainy season. June-July is the ideal time for planting the layers and seedling.

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The Guava plants are usually planted at a distance of 5-8 m. The exact Guava planting distance is decided according to variety, soil fertility, and availability of irrigation facilities. The standard plant spacing is 6 m. x 6 m. accommodating 112 plants/acre. In the model scheme, a spacing of about 6 m. x 6 m. with a population of 110 plants per acre has been considered which was observed in areas covered during a field study. High-density planting causes erect growth of branches making the plant tall, compact, and also give higher yield/unit area in the early years of fruiting. After planting, irrigate crops immediately, then irrigate on the third day, afterward irrigate depending upon soil type and climate conditions. Irrigation is not necessary to well establish orchards. Young plantation required irrigation at the weekly interval in summer months and 2 to 3 irrigation during the winter month. Avoid flood irrigation during the flowering stage as it leads to excessive Guava flower drop. Guava develops the best flavor and aroma when they ripe on the tree. A 10-year-old Guava tree gives a yield, up to 100 kg of fruit. 

Insect pests and diseases occur in Guava plant and its control measures

Insect pests of Guava plant are;

Fruit Fly (Bacterocera Dorsalis) of Guava pests

Fruit flies are the common and serious pest of the Guava tree. The flies lay eggs on the surface of Guava fruits at the color break stage. On hatching, the maggot enters into the Guava fruit and feeds on soft pulp. When Guava fruits are cut open the white maggots are seen in the flesh.

Management

• Clean cultivation or sanitation of orchard is important to reduce/check fruit infestation of fruit flies. Collect and dump deep in the pit the fallen infested Guava fruits. Daily cover the fruit with soil and do not leave the pit uncovered for long.
• Avoid taking rainy season crop.
• Harvest the Guava fruits when light green in color and firm.
• Give two sprays of thiodan 35EC (endosulphan) 2ml/ per liter or Sevin 50WP (carbaryl) 2g/liter, one before maturity and second at maturity. No spray must be given at the ripening stage during the harvesting of fruit.

Thrips of Guava pests

Symptoms – If the population is high then leaves can be distorted; leaves are covered in coarse stippling and appear silvery; leaves speckled with black feces; the insect is small about 1.5 mm and slender and best viewed using a hand lens; adult is dark brown to black and female has red pigmentation on abdominal segments.

Management – Avoid planting next to onions and garlic where large numbers of thrips can build up; use reflective mulches early in growing season to deter thrips.

Guava Shoot Borer (Microcolona technographa)

It is a serious pest in the Guava nursery and it damages the tender shoots. The infested shoots dry up which can be located from a distance by the presence of fine black growth on the plant leaves.

Management – Spray (monocrotophos) 36EC Nuvacuron by 2.8 ml per liter or (chloropyriphos) 20EC Dursban about 4.5 ml/liter or Quinalphas about 4 ml/liter of water to manage the borer.

Bark- Eating Caterpillar of Guava pests

Symptoms – The infestation of this pest can be identified by the presence of irregular tunnels and patches covered with silken web contains excreta and chewed up wood particles on the shoots, branches, stem, and main trunk. Shelter holes may be seen particularly at the joints of shoots and branches. The young shoots dry and die away giving sickly look to the Guava plant.

Management

• Keep the orchard clean and healthy to prevent the infestation of pests.
• Detect early infestation by periodically looking out for drying young shoots.
• Kill the caterpillars mechanically by inserting the iron spike in shelter holes made by borers at the early stages of infestation.
• In case of severe infestation, remove the webs and insert the swab of cotton wool soaked in 0.05 percent dichlorovos or inject water emulsion of 0.05 percent monocrotophos and plug the holes with mud.

Diseases affected in Guava tree

Guava Wilt

Wilt in Guava tree is caused by a fungus Fusarium solani or Cephalosporium sp. or Rhizoctonia sp. The symptoms appear on the infected trees many months after roots have been attacked by the fungi. Sparse foliage, yellowing of Guava plant leaves, and tree wilting are the symptoms. Before a wilting tree can flower profusely and set fruit which remains small. Overbearing is due to the stress of damaged plant roots. In the plant roots, the cambium between the bark and wood show discoloration. Replant Guava trees in the same pits bear fruit for few years and are again attacked by the fungi. Refilling of the gaps must be done after treating the soil with fungicides.

Guava wilt is a dramatic and devastating disease of plants that becomes noticeable with the onset of the rainy season. The plant can develop light yellow leaves and sag noticeably, prematurely shed fruits or defoliate entirely. There’s no cure for wilt infections in Guava trees, but good nutrition, including heavy feedings of nitrogen after fruiting, and protecting roots from damage can help stave off the wilt disease.

Control

Plant Guava m well-drained fields. Avoid flooding the Guava field while applying irrigation and apply 15 g Bavistin to each plant trunks in 2 liters of water.

• Uproot and burn the wilted Guava trees along with all roots.

Fruit Rot

This disease is caused by fungi Gloeosporium psidii and Phytophthora parasitica. Fully mature Guava fruits are more prone to fungal attack. The center of a lesion has pink sticky spore-mass characteristics of the anthracnose disease and fruits rot completely within 2-3 days. The fungi attack the twigs and branches of the tree during the rainy season, resulting in the die-back of shoot from the distal end.

Control

• Rain or irrigation water should not be allowed to stand in the Guava tree basin around the trunk.
• Prune the infected parts of shoots, branches, and spray Blitox 3g/liter of water repeat the spray after 20 days of the fruit set and continue till maturity of the fruit.
• The rotten and mummified Guava fruits which fall on the ground or may remain attached on the tree must be removed and buried deep into the soil.

Stylar end rot

Only affecting Guava fruit, this problem often surfaces once fruits are developing. You’ll notice that the bloom end of the fruit discolors and the area spreads out until the fruit becomes brown to black, as well as soft. Though it may appear similar to blossom end rot in garden plants like tomatoes, stylar end rot is believed to be caused by a fungal pathogen. Once a fruit is infected, it’s not salvageable, but you can protect the rest of the crop with a fungicidal spray. After fruiting, picking up fallen debris, thinning Guava, and increasing air circulation by moving close-by plants further away can help prevent reinfection.

Anthracnose

Anthracnose is a common fungus that is a problem for a wide range of plants, including Guava. Dark-colored lesions on mature fruit which become covered in pink spores; lesions coalesce to form large necrotic patches on the surface of the fruit. This fungal disease, like many others, can survive on dead tissues and is then spread by rain splashing, so if the plant has had problems in the past, a fungicide regiment may be called for. If your bush is older or hasn’t formed in a while, look for anthracnose-resistant varieties for better success.  The method of controlling the Anthracnose disease is to plant resistant Guava cultivars; systemic and non-systemic fungicides are effective at controlling this disease and applied shortly before flowering and during fruit development.

Algal leaf spot

Symptoms – Orange, rust-colored, silky tufts on both upper and lower surfaces of leaves which turn reddish-purple as they mature; a dark-colored necrotic spot remains on the leaf; bark on twigs and branches can be cracked; young stems and fruit may be attacked.

If you notice rusty or brown spots that emerge during humid weather, it can be a variety of parasitic algae infecting your Guava. Although algal leaf spot is harmless to both plant and fruit, severe infections can reduce vigor, decreasing the energy the plant has to put into developing fruits. Very severe infections can result in black sunken spots on the Guava fruit itself. The best treatment is to do all you can to decrease the humidity around the plant, including pruning it and nearby plants to allow better airflow to all parts of the canopy. Algae thrive on high relative humidity, so the more the wind can blow through; the less likely it is to survive next season.

Management

• Algal leaf spot disease can be reduced by maintaining tree vigor with cultural techniques such as proper fertilization and irrigation, proper pruning to enhance air circulation within the canopy and sunlight penetration, managing weeds, and wider Guava tree spacing.
• Managing insect, mite, and foliar diseases increase tree vigor and lessen susceptibility to this disease.
• Spray Copper oxychloride about 0.25%.

Commonly asked questions about Guava farming

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Which fertilizer is best for Guava?

Mix 6-6-6-2 fertilizer into soils beginning of the growing season and then 3 to 4 times during the growth period. A fertilizer high in potassium is the best fertilizer for Guava trees to increase Guava fruit production.

Does the Guava tree need a lot of water?

Guava trees prefer full sun. Guavas have survived dry summers with no water, though they do best with regular deep watering. The ground must be allowed to dry to a depth of several inches before watering again. Lack of moisture will delay bloom and cause the Guava fruit to drop.

What is the lifespan of the Guava tree?

Guava trees grow rapidly and then fruit in 2 to 4 years from seed. They live about 30 to 40 years but productivity declines after the 15th year.

Why is my Guava tree dying?

It looks like the Guava tree is infected with anthracnose disease (fungal) caused by Colletotrichum gloeosporioides. It infects plant leaves, petioles, stem, and fruits. It results in immature falling of plant leaves, fruits, and young shoots. On Guava leaves, the fungus causes large, irregular dead spots at the tip or on the margin.

Why do Guava leaves turning yellow?

Most plants will turn yellow as a sign of stress and if the weather is exceptionally hot or cool, or wet or dry, this could be the culprit. There is a chance that the yellowing leaves are a symptom of nematodes. Then, there are a number of nematodes that attack Guava tree roots.

The conclusion of Guava plant pests and diseases

It is very important to control Guava pests, diseases for better plant growth, and quality produce. You may also check this: Growing Guava in Pots from Seeds and Cuttings.