Six Predator Bugs To Use For Hemp

If you’re growing industrial hemp, like with any plant, you’re going to have to deal with pests. You’ll want to develop integrated pest management, including preventative monitoring measures and control. Many chemical treatment products are not regulated for hemp, so using predator bugs to control pest populations is a great organic approach.

It’s important to note that predator bugs need to be applied as a preventative control measure, before large infestations of pests have taken hold. Use the following six predator bugs on your hemp crops to prevent some of the most common hemp pests.

Trichogramma brassicae

The T. brassicae wasp lays eggs inside the host egg, producing up to 50 wasps per egg. In testing, they seem to do well in controlling populations of caterpillars, corn earworm, and army worm on hemp. Use T. brassicae for greenhouse or field-grown crops. Maintain temperatures between 80-90℉ if possible and do not allow temperatures to drop below 40℉. These wasps are most effective and long-lasting at 60% humidity with long days. 

Encarsia formosa / Eretmocerus eremicus 

Release this mix when you spot whiteflies on your plants. These two types of wasps act as external and internal parasites during the second and third stages of whitefly development. Each female wasp can destroy up to 150 whitefly eggs. The mix does best released in the early morning or evening when there’s low daylight and cooler temperatures. Maintain temperatures of 70-95℉. Don’t worry about the slowing of these predator bugs’ production cycle, as they are non-diapausing. 

Dalotia coriaria

D. coriaria, also known as Rove Beetle, is a soil-dwelling insect especially effective at feeding on the larvae and eggs of fungus gnats, thrips, and root aphids. They are heavy consumers of any soft-bodied arthropods larvae in the substrate, and they will feed year-round without diapause. The adults and larvae are predatory. Maintain a temperature above 60℉ and below 90℉ with 50-80% humidity for best results. Rove Beetles are excellent for controlled or greenhouse environments and can move from plant to plant on their own. 

Aphidius colemani / Aphidius ervi

This mix of two parasitic wasps works well together to attack aphids, including the cannabis aphid. Aphidius ervi attack larger aphids while A. colemani tend to parasitize smaller prey. This pair is our top beneficial predator to fight aphid infestation. Maintain temperatures around 70℉ and 60-70% humidity, but don’t worry about day length for these year-round hunters. 

Neoseiulus californicus

N. californicus will eat thrips and even pollen when other prey is unavailable but mostly prefers mites. We’ve had success using it as a predator on hemp for two-spotted spider mites, russet mites, and broad mites, as well as thrips. They’ll thrive in a wide range of temperature (50-90℉) and humidity (40-70%), but they do need at least 16 hours of daylight. Each N. californicus predatory mite will eat about five mites per day, so they are most successful in smaller populations of pests for long-term control. 

Phytoseiulus persimilis

P. persmilis are .5 mm predatory orange mites that feed primarily on two-spotted spider mites at each stage of the spider mite’s life cycle. Each P. persmilis eats 5-20 pest eggs or pests a day, and if they run out of prey indoors, they will feed on young thrip or become cannibalistic! In outdoor environments, they’ll migrate to find food when they’ve destroyed the spider mite population. Maintain temperatures above 82℉ with 70% or higher humidity and 16 hours of daylight. In this ideal scenario, P. persimilis reproduces more quickly than the two-spotted spider mite and can bring the pest population to extinction. 

To learn more about pest control for hemp, check out our article on How Terpenes Affect Pests. As always, please reach out to us with your specific questions about growing industrial hemp!