6 Beneficial Bugs That Help Protect Your Crop

A couple of months ago we discussed early-season insect pests, how they affect your crop, and how to identify them. (If you missed it, you can reread it here: Early Season Pests). But what about the good bugs that help us out?

We have several groups of insects in our cropping systems that are prevalent during spring and help play a role in pest control. It’s just as important to monitor the number of these beneficial’s as it is their bad relatives. A high population of beneficial’s will help keep pests such as aphids and caterpillars down and may influence if, and what, you need to spray.

Here’s a list of a few of the beneficial insects that you may encounter:

1. Parasitic Wasps

The adult wasp will vary in size from 1-80mm long, and their colour ranges from completely black to bright orange. The wasps have two sets of wings which can be clear or dark coloured. You can find evidence of the presence of smaller Aphid Parasitic Wasps by finding aphid mummies on plants. The adult wasp will lay eggs inside the aphid, where they’ll hatch, develop, and eventually kill their host — leaving behind a mummified skeleton. There are also several Caterpillar Parasites Wasps that control Native Budworm and Diamondback Moth.

2. Ladybird Beetles

Commonly known as ‘ladybugs.’ Most people who grew up with a garden won’t need help identifying these. The adult ladybird is round or oval in shape, shiny, and will typically have patterns of black on top of a red, orange, or yellow body. Their larvae are elongated and mostly grey or black with orange markings and black legs. They’re also not as gentle as their name suggests. Both the adults and larvae will prey on aphids, leafhoppers, thrips, moth eggs, and small caterpillars.

3. Lacewings 

Adult Lacewing’s are 6-20mm long, with long antennae and wings that show veins that give them a lacy appearance. There’s a high chance you would have found them in your sweep net during spring sweeps. The larvae vary in shape depending on species, but all have a tapered body and sickle-shaped mouthparts. Brown Lacewing’s are predatory as both larvae and adults. However, the Green Lacewings are only predatory as larvae. They will consume aphids, thrips, caterpillars, and moth eggs.

4. Damsel Bugs

The adult Damsel Bug is 8-12mm long, with a slender light brown body with long antennae and large protruding eyes. The nymphs are similar, however, smaller in size and lack the wings of the adults. Both adult bugs and nymphs will feed on soft-bodied prey, including moth eggs, aphids, and small caterpillars. Rather gruesomely, they’ll hold their prey in their enlarged forelegs and use their piercing mouthpart to suck out the insect’s body contents.

5. Hoverflies 

The adult Hoverfly is 4-10mm long with dark coloured flattened bodies with black and yellow markings. Their larvae are legless, green in colour and look similar to grubs, and are often mistaken for pests like diamondback moths. The adults feed on pollen, but their larvae will attack a range of soft-bodied insects and have a particular appetite for aphids.

6. Shield Bugs 

The Spined Predatory Shield Bug is around 12mm long, and has a grey-brown shield-shaped body with a light marking in the middle of it’s back. They also have a pair of prominent spines on either side of their thorax. They will attack various caterpillars, including native budworms and armyworms by using their piercing mouthparts to suck out insect body contents.

Though we’ve covered off the main ones, some other beneficial insects to keep an eye out for include:

• Carabid beetles
• Spiders
• Dragonflies
• Damselflies
• Common brown earwigs (not European earwig)
• and worms.

If you have problematic pests, as well as some of these beneficial insects in your crop, talk to us. There are certain thresholds we can use to determine whether you require an insecticide spray or if the beneficial’s are keeping other pests in check. As we said, it’s important to monitor the levels of these good guys as well as the bad guys. Depending on their levels, a softer insecticide might be the best option to limit harm. Keep an eye out for these and make an educated decision about what’s best for your crop. If you need any help to identify any insects in your crop, give us a call.