Wednesday, 6 October 2021

A pest from Africa

The southern green stinkbug (Nezara viridula) is a relatively new pest that originates from Ethiopia. The pest has a large number of host plants, but in horticulture this bug is mainly found in bell pepper cultivation. In the first instance, in The Netherlands, the southern green stink bug was only spotted at the end of the summer, but the bug has also shown itself earlier in the season in recent years.

Females lay around 30 to 130 eggs at a time. They do this in "glued together", yellow and white clusters at the bottom of the leaf. If they are just laid, they look like little pearls. Depending on the temperature, the eggs hatch after 4 days to 3 weeks and the empty eggs remain on the leaf. The nymphs initially stay together and do not yet affect the plant. They then go through different stages, each time shedding their skin, with each stage having a different appearance. In the fifth stage, the bugs begin to spread over the plant and eat it.

With its sucking mouth parts, the bug penetrates the plant tissue, preferably with young plant parts, growing shoots and fruits. It takes vegetable juice, but also injects toxic saliva, which ends up in the juice stream. The saliva destroys the tissue. With peppers you see necrotic tissue on the fruits.

The wounds caused by the southern green stink bug are an additional problem. Fungi and bacteria can easily penetrate the plant through these wounds, so that the plant can become infected more quickly.

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