Pests and diseases of cherimoya

Pests and diseases

Cherimoya trees grown in New Zealand have relatively few problems with pests and diseases.
The major pests are:

–	Opposums, which can cause structural damage while climbing round reaching for cherimoya, so their numbers need to be kept under control.
–	Cicadas, which also cause structural damage by creating weak points where they lay their eggs deep into branches. Remove and burn any damaged branches that won’t affect tree growth and shape Ciciada egg laying damage
–	Thrips, that scrape the chlorophyll off leaves, therefore reducing the leaves’ photosynthetic capabilities. Spraying early or the continual removal and burning of infected leaves can significantly reduce numbers. Thrip damage to leaves

Other potential pests include:

–	Snails, which can be controlled by chickens or by applying copper strips around the trunks.
–	Mealybugs, which suck the sap (and the goodness) from leaves. They need to be sprayed to be removed.
–	Ants, which can carry mealybugs onto trees, can be partly controlled by ant insecticide on masking tape, or white paint with diazinone, applied around the base of the trunk preventing ant access. The masking tape prevents damage to the tree from chemicals.

Some of the problem pests overseas are:

–	Fruit fly (Anastrepha sp.)
–	Leaf miner (Leucoptera sp.), for which you must collect and burn affected leaves and apply systemic insecticides.
–	Seed borer (Bephrata maculicollis), which deposit eggs on the surface of developing fruit. The larvae (which are very difficult to combat) invade the fruit and consume the seeds, causing premature and defective ripening, rendering the fruit susceptible to fungal diseases. Borers attack trees in Argentina, reducing their life span from 60 to 30 years.
–	Caterpillars (Thecla sp. and Oiketicus kubeyi), which may defoliate the tree.
–	Scale insect (Conchaspis angraeci), which attack the trunk and branches.
–	Coccid (Pseudococcus filamentosus), which attack fruit in Hawaii.

The main diseases are:

–	Botrytis (grey mould), which can cover fruit after heavy rain.
–	Phytophthora root rot, caused by poor soil drainage, overwatering (or watering the trunk) and bad air circulation (which increases humidity)
–	Anthracnose.

Other potential disease include:

–	Armillaria rot root fungus and Verticillium. Don’t plant trees in old vegetable gardens, or near tomato or other plants that are prone to verticillium.
–	Crown rot, which can kill trees that are damaged by frost, growing in saturated soil, or that have trunks subjected to frequent irrigation.
–	Sooty mould, which can occur on leaves and fruit where aphids, mealybugs and other insects have deposited honeydew.