Banana crop protection

Being grown in a warm and wet environment, bananas are highly susceptible to root, leaf and fruit diseases. Leaf diseases such as Sigatoka (black and yellow) have a major effect on production. Sigatoka reduces leaf area, significantly limiting photosynthetic capacity. Common practice is to cut and remove leaves infected at levels of 50% or more Sigatoka, so as to minimise its spread. Care needs to be taken not to reduce the number of leaves below a critical level. In addition, up to 50 applications of fungicide may be applied annually in order to keep on top of the disease in regions most at risk.

The dominant root disease is Fusarium oxysporum, also known as Panama disease. It is a particular problem in Gros Michel. In addition, there are a range of fruit rots from the general Verticillium, Trachysphaera, Colletotrichum, Fusarium and Botryodiplodia. Pest control is essential in most regions. The banana weevil borer and burrowing nematodes attack the rhizome and pseudostem, weakening the plant and leading to breakage. Thrips feed on immature fruit and can cause superficial damage to fruit peel.

Soil cultivation is rarely practiced in ratoon crops due to their shallow-rooted nature, thus weed control is achieved by using herbicides, machetes or hoes, and by mulching. Bunch covers are used to protect the developing bunch, reducing fungicide speckling, bunch rubbing and dust gathering around the bunch. 

In cooler environments, covers warm the bunch and reduce the impact of strong winds, improving bunch development time and shortening the production cycle. In hotter, tropical conditions, physiological damage due to overheating under bunch covers needs to be minimised to prevent rotting of fruit, premature ripening and pest problems. This is overcome by using perforated bunch covers impregnated with pesticides. At the same time as fruit covers are placed over the fruit, plastic covers may be placed between the fingers, to cushion the fruit and prevent subsequent physical rubbing and damage during growth, harvesting or transportation to the packing shed.