Ruud Kleinpaste: Passive pest control

Author
Ruud Kleinpaste,
Publish Date
Sat, 5 Oct 2019, 11:46AM
Phacelia is great for predatory hover flies that devour aphids. (Photo / NZME)

Ruud Kleinpaste: Passive pest control

Author
Ruud Kleinpaste,
Publish Date
Sat, 5 Oct 2019, 11:46AM

Beneficial Plants

This is a good weekend to get into the garden and plan ahead for crops and fruit - and pest control. 

Passive biological control is always a good strategy: Instead of having to spray against the various pests on your plants, why not let the natural predators and parasites do it?

The animals you’d want to attract to your place are insectivorous birds, of course, but birds can only do so much. They are often quite omnivorous and will eat a range of insects: pests as well as Beneficial insects!

How about getting some specific parasitoids on board; small parasitic wasps that will lay their eggs inside the nuisance caterpillars, in mealybugs, scale in sects and aphids.

These parasitoids need to feed as adult insects before they can mate and lay their eggs; Flowers with just the right mix of pollen and nectar will do nicely: it fattens up the parasitoids and keeps them in perfect condition.

Here are some of the flowers that will attract them:

Phacelia (blue Tansy); it’s great for predatory hover flies that devour aphids. Sow the seeds now, but watch out if this plant is getting a bit weedy in certain environments.

Another excellent flower – this one’s to grab the attention of parasitic wasps - is Buckwheat. A nice small plant with white flowers; it fits in empty spaces and under fruit trees, in berry gardens and productive vegetable gardens.

Flowering Umbelliferous plants attract a wide range of beneficial insects: leave your parsley go to flower and “seed”, carrot flowers, Queen Anne’s Lace and such nice umbels of flowers, are usually full of parasitoids and predators too.

Similarly: try some dill and fennel.

The mixed seed packets (Kings Seeds etc) that benefit “pollinators” will also benefit the beneficials.

Finally: there are a heap of native flowers that seem to be attractive to the beneficials

Hebe is such a flower, but also Manuka and Pohutukawa. Not something you’d sow and utilise within a few weeks or months, but worth thinking about for long-term planting to facilitate free pest control!

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