Pruning and managing existing avocado orchards

Pruning of avocado trees is becoming an important part of orchard management. Producers are more aware of the difficulties with the management of large trees in overcrowded orchards. Spraying is difficult and often ineffective and fruit picking becomes more formidable, the larger the trees become, with yield and fruit quality declining rapidly in such orchards. Alternate bearing also becomes more ensconced along with all the fruit quality and economic implications thereof. The underlying problem is a lack of light interception and penetration into the dense overcrowded orchards. Die-back of inner branches creates vast empty canopies moving the crop ever higher. In the past, practices such as tree thinning or staghorning of trees were used to alleviate the overcrowding problem. These were only temporary measures as the avocado trees grew back vigorously diminishing the effect of thinning or staghorning within two to three years. The ARC-ITSC has shown over the past five years that a well structured and managed pruning programme can alleviate the problem of overcrowding. Pruning trees to a pyramidal shape can increase sunlight interception and penetration with the renewal of bearing wood and an improvement on yield and fruit quality. Initial heavy pruning of an overcrowded orchard may result in the loss of one year's crop. Timeous pruning of orchards not yet overcrowded can, however, keep the orchards in production for their entire lifespan. In this paper the principles and practice of mechanical and selective pruning will be discussed. The use of bio-regulators and cincturing to curb vigorous regrowth and induce fruiting will also be briefly discussed.