The crater-like appearance is the typical noticeable symptom of fruits rather than on leaves. Seasonal occurrence and factors of abundance High rain falls during August and September months favors the disease development.
Closer or Dense planting without canopy management. The availability of free water in the guava orchard with dew or rains encourages spore production and its dispersal around the canopy. Management practices Pit treatment with formalin and kept covered for 3 days and transplanting should be done after two weeks to avoid the disease.
Dip the fruits in ppm tetracycline for 20 min for harvested fruits. Apply biocontrol agents like Streptosporangium pseudovulgare on fruits before the emergence of symptoms. Bagging of fruits at the fruit formation stage. Sharing is Caring. Leave a Reply Cancel reply Your email address will not be published. The insect lays eggs on the soft skin of fruits and the egg period is about days. Maggots are pale cream, cylindrical, mm in length and larval period is days.
Maggots pupate in the soil, the pupal period is 7 — 13 days. Adults are smoky brown with greenish-black thorax having yellow marking on it.
The egg period is days and the larval period is 18 to 47 days. Caterpillar is dark brown with short hairs and white patches all over the body. Larvae pupate inside fruit but occasionally outside even, attaching themselves to fruit stalks. The pupal period is 7 to 34 days. Males are glossy, bluish-violet, whereas the female is brownish-violet with an orange patch on the forewings. Four generations are completed in a year. The egg period of mealy bugs is about 5 to 10 days.
Crawler nymphs are orange, whereas females and males are with 3 and 4 nymphal instars respectively. However, adult females are pinkish and sparsely covered with white wax. Insects attain single generation per month, however, the life cycle extends in winter months. Maggots bore into the fruits and feed the soft fruit pulp.
The infested guava fruits show small cavities with dark greenish punctures and when cut open, the wriggling maggots are seen inside the fruit. Infestation leads to rotting and dropping of fruits. Larvae bore inside the developing fruits. Larvae feed on pulp and seeds exhibiting round boreholes on the fruits.
Infested fruits are also attacked by secondary microbes like bacteria and fungi, and the guava fruits ultimately fall off and give an offensive smell. Both nymphs and adults suck the cell sap leads to crinkling and yellowing of leaves with rotting of berries.
Whitey growth of insect pests is seen on all the plant parts. Spray fenvalerate 20EC 1lt or malathion50EC 2lt in to lt water per ha. Rake the soil around the tree and apply lindane dust 1. The spray may be repeated at fortnightly intervals depending on the severity of the attack.
Young juvenile nematodes hatch from the eggs in the soil and migrate towards the root tips of the susceptible plants. Stunting and yellowing of plant foliage with early wilting. Removal and destroying of nematode infested trees. Fusarium oxysporum f. The method, ground layering is easy, economical and followed on large scale.
Planting and Season : The guava can be planted at any time of the year. However, June planting followed by January planting is more successful and very well adopted. A spacing of 7x7 or 6x6 sq. Short duration crops, preferably vegetables are taken. Care of young orchard Gap filling should be done within a month. Supporting and training to young trees is necessary to get uniform stand of all the plants. Necessary provision for wind breaks is useful. Plants like susbenia, Mulberry, etc. Special Horticultural Treatments Training and pruning : The guava plants are trained to a single stem.
No branching is allowed upto the height of 1 m on main trunk. Pruning to young plants is necessary to have uniform and well balanced growth and shape. Judicious pruning is also recommended prior to flowering of selected bahar. Pruning increase the productivity and makes the various operations like spraying, harvesting easy. Bahar treatment: This consists of withholding of water prior to flowering of bahar. Normally there are three bahars i. Mrig bahar, Hast bahar and Amba bahar, out of which only one is selected depending on climate and market.
Root pruning and shoot pruning are also followed as a supporting treatments at bahar treatment. Bending of branches: This practice is only followed in certain erect growing types to improve flowering. Excess of water adversely affects the quality of the fruits besides it favours excessive vegetative growth and invites fungal diseases.
Drip irrigation and fertilization are the latest techniques, which economise the use of water and fertilisers. However, during the vegetative growth period moisture is necessary and the system should be on as per requirements. Application of manures and fertilisers The amount of fertilisers and manures depend on soil, variety, yield potential and age of the tree. Land is prepared during the summer season by ploughing, harrowing, leveling and removing weeds. Plants are vegetatively propagated by budding, inarching or air layering.
Planting is done during the rainy season. June-July is the ideal time for planting the layers and seedling. The plants are usually planted at a distance of m. The exact planting distance is decided according to variety, soil fertility and availability of irrigation facilities. Standard spacing is 6 m. By increasing the plant density, productivity can be increased.
In the model scheme, a spacing of 6 m. Square system of planting is generally adopted. Pits of 1x1x1m. Time of fertilizer application depends on the region and crop variety. In north India, fertilizer is applied in the first week of May for rainy season crop and in first week of July for winter season crop. The plants are manured twice a year, first during June-July and second by during October. A fertilizer dose of g. N, g. K in Northern Region, g. P and g. K in Eastern Region, g.
K in Southern Region and g. Guava is mostly grown under rainfed condition. During winter season, irrigation is provided at an interval of days and in the summer months it is provided at an interval of days by the ring method. Drip irrigation has proved to be very beneficial for guava. Besides substantial increase in size and number of fruits is observed. Training of plants in young stage is essential in order to build a strong framework and to avoid weak crotches.
Fruiting trees are pruned to check overcrowding in the orchard. The plants are trained as low headed trees to facilitate multiple hand pickings. Pruning is usually recommended after harvesting or in spring. Summer pruning is generally avoided as the plants get damaged due to sun burn. Weeds are usually removed by shallow cultivation. Green manuring is usually done during rainy season. Pre-emergence use of diuron 1.
Dry leaves or straw are used as mulching material. Mulching can also be done either with black polycthylene sheet or with organic materials.
Mulching the soil at least twice a year helps in conserving moisture and improving the fruit quality. Leguminous crops or vegetable can be grown as intercrops during the first three years of planting provided irrigation facility is available. The main diseases reported are wilt, fruit canker, fruit rot, anthrachose and grey leaf spot. Bronzing of guava has been observed in places having low soil fertility and low pH.
Affected plants show purple to red specks scattered all over the leaves. Under aggravated condition, total defoliation and fruits characterized with brown coloured patterns on the skin, with reduced yield are noticed.
Foliar application of 0. Pre-flowering sprays with 0. Spraying of copper sulphate at 0. The plants start bearing at an early age of years but they attain full bearing capacity at the age of years. The yield of a plant depends on its age, cropping pattern and the cultural practices. A 10 year old plant yields about to kg. If both rainy and winter season crops are taken, more yields may be obtained in the rainy season.
Guavas are harvested throughout the year except during May and June in one or the other region of the country. However, peak harvesting periods in north India are August for rainy season crop, November- December for winter season crop and March-April for spring season crop.
In the mild climatic conditions of the other parts of the country, the peak harvesting periods are not so distinct.
Guava fruits develop best flavour and aroma only when they ripen on tree. In most of the commercial varieties, the stage of fruit ripeness is indicated by the colour development which is usually yellow. For local markets, fully yellow but firm fruits are harvested, whereas half yellow fruits are picked for distant markets. Fruits are harvested selectively by hand along with the stalk and leaves.
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