Water guava fruit size and quality are influenced by various factors, including water and nutrient availability, fertilization, pest and disease control, thinning, packing, and harvesting.
A. Water & Nutrients
Water should be available in sufficient quantities, as lack or excess water can cause guava flowers or fruits to fall off. During the dry season, plants require 5-10 liters of water per day, which should be sprinkled in the morning, afternoon, and evening.
B. Fertilization
Manure and compound NPK fertilizers are used. About 40 kg of manure per plant is applied at the beginning of the rainy season. Fertilizers are sprinkled and mixed into the soil around the plant, from the stem to the outer line under the crown. Twice a year, when the plants begin to mature, apply a compound NPK fertilizer with high P and K content (1:3:3) at a dose of 250 grams per plant.
The first fertilization should be done before the plants flower, either at the beginning of the rainy season or the beginning of the dry season. Apply the second compound NPK fertilizer with high N (2:1:1) before small pruning, after flowering. If the soil is acidic, dolomite can be applied together with the fertilizer.
It is important to avoid disturbing the roots of plants when applying compound NPK fertilizer. This is because hoeing can cause root injury, which may result in the loss of flowers or fruits. Instead, dissolve the fertilizer in water and apply it under the outer crown of the plant.
C. Pest and Disease Control
When the plants begin to flower, pests may appear. To control these pests, apply a low dose of contact insecticide at a rate of approximately 1 ml per liter of water. To prevent root-destroying pests caused by beetle larvae that live in moist soil, avoid disturbing the roots, as this can trigger fruit and flower drops.
D. Fruit Thinning
Thinning or fruit selection can result in larger fruits. Thinning involves removing fruits that are infested with pests or have incomplete growth. Nested fruits are typically 1-2 weeks old after fruit formation.
When selecting fruits to retain, choose those near the main stem. However, for certain species where the fruit comes out at the end of the twig, this does not apply. Only retain a maximum of 4-5 fruits per cluster, depending on the size of the stalk. Select fruits that are directly attached to the fruit stalk. Despite thinning, natural fruit drops can still occur due to the characteristics of water guava plants.
E. Fruit Wrapping
Fruit packing is performed to ensure that the fruit remains smooth and free from deformities or soiling caused by fruit fly infestations. Wrapping should be done 1-2 weeks after the fruit set using light or dark-colored plastic bags. The bottom of the wrapper should be perforated to allow for air circulation, preventing retained fruits from rotting and inviting disease.
It is important to tie the top of the wrapper to prevent rainwater from seeping in. The wrapping should not be too narrow as it may disrupt the fruit enlargement process. Control should be conducted every 2-4 weeks. In case of a pest attack, insecticide should be sprayed immediately. Pesticide spraying on the fruit should be stopped approximately 4 weeks before harvest.
Harvesting of water guava should be done selectively every 2 days when the fruit is ripe, as it deteriorates quickly. The maturity level of water guava is not simultaneous, so selective harvesting is necessary. It is important to cut off the fruit stalk during harvesting to stimulate the emergence of new branches for fruit production in the following season.
