Flies, particularly the onion fly (Delia antiqua) and the bean seed fly (Delia platura) pose significant threats to onion crops. These pests lay their eggs near the base of onion plants, leading to the hatching of larvae that tunnel into the bulbs, causing extensive damage. The bean seed fly is especially notorious for attacking young onion plants, while the onion fly targets mature crops.

Control of flies in onion

In onion crops, the control of onion fly and the control of bean seed fly can be effectively achieved through the use of beneficial nematodes. Nematodes are natural predators of the larvae of these flies. Steinernema feltiae (Capirel) and Steinernema carpocapsae (Casea) are both beneficial nematode species that infect and kill the larvae of the onion fly and the bean seed fly.

Thrips poses one of the biggest challenges in onion crops, especially the onion thrips (Thrips tabaci). Onion thrips causes damage by piercing and sucking plant tissues, leading to distorted leaves and reduced photosynthesis.

Thrips control

A natural solution for thrips control in onion crops, is Amblyseius andersoni (Anso-Mite, Anso-Mite Plus). This predatory mite preys on thrips larvae. Additionally, the predatory bug Orius spp. (Thripor-I, Thripor-L) controls thrips at various life stages.

The presence of various moths and caterpillars such as the cotton leafworm (Spodoptera littoralis), Spodoptera cosmioides, southern armyworm (Spodoptera eridania), fall armyworm (Spodoptera frugiperda), diamond back moth (Plutella xylostella), and beet armyworm (Spodoptera exigua) pose a threat to onion crops. Also, cutworms (Agrotis spp.), such as black cutworm (Agrotis ipsilon) and the turnip moth (Agrotis segetum) can have a damaging effect on onion crops, causing substantial damage to the leaves and compromising the plants' overall vitality. These pests are mainly a challenge in the tropics.

The stone leek leaf miner (Liriomyza cepae) stands out as a pest in onion cultivation, leaving its mark through the characteristic serpentine mines it creates on onion leaves. These leaf miners not only compromise the aesthetic appeal of the crops but also weaken the plants, potentially reducing their yield.

Aphids are a significant threat to onion crops. Aphids like the green peach aphid (Myzus persicae), the onion aphid (Neotoxoptera formosana) and the shallot aphid (Myzus ascalonicus) are the most common species occuring in onion crops. These tiny, sap-sucking insects multiply rapidly, causing extensive damage to onion plants by draining vital nutrients and transmitting diseases.