Selectively targeting caterpillars – the creepy crawly veggie garden nightmare

by | Nov 5, 2019 | Birds, Bees & Bugs | 0 comments

Summer has arrived and so have the creepy crawlies. For many garden lovers the detection of caterpillars in their veggie gardens is soul destroying, normally for two very different reasons. Firstly, the devastation of their attack and the inevitable ruin and damage to your efforts and harvest. Secondly, and often most importantly, you are then faced with the really tough decision as to ‘if’ and ‘how’ you should get rid of them…

The good news is that there is now a safe and effective biological larvicide for the control and management of a wide range of caterpillars. What is meant by the term ‘biological larvicide’? Larvicides specifically target the ‘larval’ stage of an insect and ‘biological’, as you know from previous issues, refers to the introduction of a natural enemy.

caterpillars damage

The natural enemy in question, Bacillus thuringiensis (Bt), is a beneficial soil-borne bacteria occurring naturally in soils. Bt is one of the first commercialised and most successful biocontrol products globally, and has been used since the 1950s for natural insect control. Bt is highly adaptive to different environments and is target specific, only being toxic to lepidopteran larvae. Bt has no effect on beneficial insects such as bees, ladybirds, lacewings and predatory wasps.

Larvae Pro is a commercial product that forms part of the EcoBuz Bio-Protect range and contains spores of the beneficial bacteria Bacillus thuringiensis (Bt) subspecies Kurstaki strain SA-11.

How does it work on caterpillars?

The Bt spores are activated when mixed with water. The solution needs to be sprayed onto foliage and plants affected by caterpillars, where the spores will germinate and multiply. They need to be ingested by the larvae in order to be effective, and this is achieved when the caterpillars feeds on treated plant material. Each Bt spore contains a special protein crystal that once ingested becomes active in the alkaline gut of the larvae to form a toxin that paralyses and ultimately kills the larvae.

Larvae Pro is highly specific. The Bt crystal contained in the Larvae Pro spore only activates in the alkaline gut of Lepidopteran larvae. Lepidoptera (moths and butterflies) is the second largest order in the class Insecta. Nearly all lepidopteran larvae are called caterpillars, and have well-developed heads and chewing mouth parts for feeding on plants, which makes them a common pest in gardens and agricultural crops.


Larvae Pro is easy to mix and apply, with consistent results. Spray onto the affected area as soon as caterpillars are detected, taking care to cover both the surface and underneath of leaves. Once ingested larvae will stop feeding within 24 hours and die within a few days. Larvae Pro treatment will be faster and more effective on small, young larvae. Most importantly, Larvae Pro is nontoxic, completely natural and OMRI listed (Organic Materials Review Institute). It is safe for use, for consumers and the environment, it has no withholding period so you can spray today and eat today. Larvae Pro is registered for the suppression of African bollworm, tomato leaf miner and fall armyworm on crops as listed.