Onion Thrips

Thrips tabaci

Onion thrips (Thrips tabaci) is the most serious pest of onion crops in New Zealand. Their rasping feeding causes whitening of leaves which reduces yields. However their presence in the necks of harvested bulbs and subsequent feeding damage in storage can lead to rots in storage in export shipments. The adults are small, a black colour and are winged. The larvae which cause the plant damage are thin and a white to yellow colour and are usually found in the necks of onion plants.

Related Pests

Thrips

Thrips are a rasping feeding pest that can cause economic damage on several crops including avocados and stonefruit. Their feeding causes bronzing and marking on fruit surfaces reducing the marketable value of the crop.

Downy Mildew - Onions

Peronospora destructor

Downy Mildew (Peronospora destructor) is destructive of onions in New Zealand reducing crop yields, bulb quality and storage life. First symptoms are yellow oval patches on leaves that turn brown and develop a downy grey sporulation. Favoured by moist and mild weather, Downy Mildew can quickly spread as increasing patches in onion crops.

Tomato Potato Psyllid

Bactericera cockerelli

Tomato/Potato psyllid (Bactericera cockerelli) is a devastating pest of potato and tomato crops. A sucking pest whose feeding on foliage causes yellowing, purpling and cupping of leaves, stunting of plants and reduces yields. The pysllid can also transmit Liberibactor, a bacterium like organism that affects the internal vascular transport system of plants. This negatively disrupts potato tuber quality often resulting in the “zebra chip” effect in processing potatoes.

Cabbage Aphids

Brevicoryne brassicae

The cabbage aphid (Brevicoryne brassicae) is greyish, mealy looking aphid, present throughout New Zealand and which attacks and feeds on all types of brassicas.While aphids are present in crops all year populations tend to be greatest in spring and late summer. This aphid tends to form colonies and populations can be quite large. The aphid can cause serious damage by stunting and deforming plant growth, transmitting viruses and through crop rejection through poor quality.