Slugs & Snails

Slugs, and to a lesser extent snails, are a regular pest in agricultural crops. Under the right conditions populations can be large and very significant crop losses can occur. In New Zealand the main pest species are the grey field slug and the common garden snail. Each slug can lay a significant number of eggs per year and so populations can increase rapidly. Slugs and snails are favoured by moist, cool conditions and populations are highest in lightly compacted or poorly structured soils where slugs find it easier to move around. Slugs and snails tend to feed at night, especially when it is wet, but under dull, humid conditions slugs especially can be found feeding during the day.

Related Pests

Bronze Beetle

Eucolaspis brunnea

The adult form of the New Zealand grass grub is commonly called bronze beetle (Eucolaspis brunnea). Flights of the beetles in late spring can cause damage to fruit trees including apples. On apples the beetle chews leaves and fruits causing scalloping marks on fruit.

Codling Moth

Cydia pomonella

Codling moth (Cydia pomonella) is the most serious pest of apples and pears in New Zealand. Adults lay eggs on or near fruits and the larvae burrow their way into the fruit. It is critical to control the larva before it enters the fruit as presence in fruit is a quarantine pest in several key export markets.

Woolly Apple Aphid

Eriosoma lanigerum

Woolly apple aphid (Eriosoma lanigerum) is a prevalent pest within apple orchards and can cause significant damage to the trees. The aphids (often referred to as woolly aphids) infest the aerial parts of trees and sometimes the roots, sucking sap from the plant.

Feeding damage from heavy infestations can result in knotted and galled lumps on older wood and bud damage on shoots which can negatively affect the following years crop. Fruit contamination and infestation contributes to significant productivity losses and aphid infestation of fruit calyces can present a market access problem in some markets.

Apple Leaf Curling Midge

Dasineura mali

Apple leaf curling midge (Dasineura mali) or ALCM causes characteristic leaf curling on young shoots throughout the summer. Severe infestations can retard growth and on young trees effecting tree development. Contamination of fruit by apple leaf curling midge is a major concern as it is a quarantine pest in some key export markets.