Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

_________________________________________________________________________________Eggplant Crop Development2.1 Eggplant growth stagesEggplant completes a life cycle, from seed to seed, in one season. Eggplant is usually grown for a fewmonths, although it can be cropped for over one year when growing conditions (water, fertilization, etc.)are optimal and plants are not exhausted by diseases or insect pests.General growth stages for eggplant are:• Seed.• Seedling stage: usually the periodfrom emerging seed to transplantingto the main field.• Early vegetative stage: plant with upto two branches (up to about 40 daysafter transplanting depending onvariety, climate, fertilization, wateravailability, etc.).• Late vegetative stage: period ofbranching until onset of flower buds(period from about 40 to 60 daysafter transplanting, depending onvariety, climate, fertilization, wateravailability, etc.).• Flowering stage: plant with flowerbuds and open flowers.• Fruiting stage: plant with small to fullsizedfruits.• Harvesting stage: period when plantyields mature fruits.• Post-harvest stage: the time after thefruit has harvested, and before it isconsumed or processed.These growth stages are overlapping intime, because mature fruits and flowerbuds can develop at the same time.When eggplant is cut back (ratoon), asecond vegetative stage develops,followed by a flowering, fruiting andharvesting stage.2.2 Susceptibility of eggplant growth stages to pestsWhether various pest and disease species that attack eggplant will cause economic loss partly dependson the growth stage of the plant. Injury to the older leaves at a late stage in crop development forexample, will not influence the final yield. Eggplants can compensate for a lot of injury by producing moreleaves, new shoots or bigger size fruits. When plants compensate for crop injury without yield or qualityloss, there is no need to implement control practices such as applying a pesticide. This would only be awaste of money and time. Preventing crop damage by implementing a control practice like applying apesticide is only economically justified if the benefits from implementing that practice are greater than thecosts of the practice. For fresh market eggplant fruits for example, the quality could be reduced if evenslight injury occurs on the fruits.To obtain information about the compensation ability of the eggplant, studies on defoliation and removalof shoots can be conducted. See box below.5Eggplant Ecological Guide