Nov 16, 2023

Mastering Micromus-System monitoring

A voracious aphid predator, the brown lacewing Micromus angulatus (Micromus-System) plays a valuable role in IPM control programmes providing robust, quick and effective control of this widespread pest. A true generalist, both the adults and larvae consume all significant aphid species.

While effective monitoring is a cornerstone of successful IPM programmes, Micromus adults can be difficult to spot in the greenhouse during the day due to its nocturnal nature. Closely resembling the green lacewing Chrysoperla carnea (Chrysopa-System), it is important to be able to spot the differences between these two lacewing species. Here we explain these differences and give you helpful tips to improve monitoring accuracy and efficiency.

Egg-cellent scouting

Over their lifespan, female Micromus-System adults lay large numbers of smooth, pale brown, oval, stalkless eggs close to aphid colonies. Monitoring can be simplified, and made more efficient, by marking aphid colonies in the crop where Micromus adults have been released, so scouters can return to these points to inspect for eggs. Additionally, Micromus doesn’t shy away from laying its eggs on hard, dry surfaces in sheltered places, such as under pot rims. So, to monitor for its eggs effectively, be sure to check under pots and gutters. In contrast, Chrysoperla lays its eggs on stalks.

Identifying Micromus larvae

While Chrysoperla and Micromus larvae look similar, Micromus are darker and have less pronounced hairs. On closer inspection, the first segment behind their head (pro-thorax) takes an oval shape, whereas for Chrysoperla it is rectangular. 

Micromus larvae are often found in aphid colonies. When not feeding, they seek refuge in covered places, such as beneath the calyx of a strawberry or under plant pots or picking baskets.

Where to find the pupae

The Micromus pupal case is creamy brown, approximately 5-6mm long and enclosed in a thin cocoon spun by the larva. These cocooned pupae can be found on the plant itself, on the underside of leaves, or on other smooth surfaces such as under plastic pot rims and gutters.

Monitoring nocturnal adults

Nocturnal and inconspicuous, Micromus adults are not easily observed in the crop during daytime. To monitor effectively, scouts need to look under pots, boxes, tables and gutters. They may also be observed hiding in low-growing weeds or plant debris on the soil surface. Keep an eye out for dark brown faeces on the underside of leaves, as it is a sign of their secret presence.

Informed decision making

Scouting and monitoring are vital components of successful IPM programmes. Regular and accurate collection of monitoring data, illuminating the biological balance of pests and beneficials in a crop, enables data-driven decisions when devising control strategies.

As a key component of many aphid control strategies, mastering the art of monitoring Micromus-System empowers growers to make informed decisions, based on what is really going on in the crop.