GrainsWest Spring 2021

Spring 2021 grainswest.com 27 WHO’S WHO? Now that you know a thing or two about beneficial insects, what on earth do these insects look like? Wonder no more. Below are common Prairie beneficials you may have seen or perhaps you’ve witnessed evidence of their diligent work terminating true pests. PARASITIC WASPS: Parasitic wasps are some of the tiniest and most impressive beneficial insects out there. Small and stealthy, they are easily missed by the untrained eye. But they are big players in provid- ing free pest control. Here are three of the main wasps buzzing around Prairie crops. Bracon cephi focuses specifically on wheat stem sawfly, which has been a longtime issue for Prairie farmers. Only a few millimetres in length, this wasp lays its eggs in stems infested with wheat stem sawfly. In an invisible showdown inside the stem, the B. cephi larva hatch, eat and kill the sawfly larva, protecting yield. The wasp larva then transforms into an adult in the stem, starting a new generation. The only trace of this beneficial insect’s presence is the tiny exit hole it makes as it leaves the stem. Macroglenes penetrans (see photo on page 24 ) is the main parasitoid of the orange blossom wheat midge, Sitodiplosis mosellana . This wasp kills an average of more than 30 per cent of overwintering cocoons of the wheat midge by laying its eggs directly inside the midge. In springtime it bursts through its host, killing it instantly. Annually, this helpful insect saves farmers millions of dollars on input costs. Tetrastichus julis is a seriously beneficial insect. Adult females lay their eggs inside the larvae of cereal leaf beetle. The wasp larvae hatch and eat the beetle larvae from the inside out, preventing the pest from completing its life cycle. Half or more cereal leaf beetles in a field may be parasitized by T. julis . This pipsqueak of a beneficial has likely prevented the outbreak of cereal leaf beetle as a more serious pest in Western Canada. DAMSEL BUG: The common damsel bug, Nabis americoferous , has semi-raptorial front legs for grabbing prey. It stabs its “beak” into its prey, injects a digestive enzyme then sucks out the digested insect insides. Cool, gross and true all at the same time. GROUND BEETLE: Poecilus lucublandus is one of the most common ground beetles on Prairie farms. While it is mostly a predator, like most carabids, it is also an omnivore and will eat weed seeds and whatever else it may encounter. COMMON GREEN LACEWING: Chrysoperla carnea in its larval stage is aptly called an aphid lion for the voracious way it attacks its prey. Ever hungry, green lacewing larvae can eat about 33 aphids daily. A green lacewing larva also has an appetite for thrips, mites and certain caterpillars. The larva’s front mandibles make an excellent set of grabbers to pull in yummy pests. LADY BEETLES: The Coccinella septempunctata is perhaps the most well-known beneficial insect because it is cute and often appears in children’s storybooks . A lady beetle is easily identified by its seven spots and its love of munching on aphids. Even as they mature, they are great hunters and in their larval stage they almost resemble little alligators. These colourful beneficials may eat up to 5,000 aphids in their lifetime. PAINTED LADY BUTTERFLY: Cheerful, majestic and full of grace, this butterfly is also a vicious killer known in Latin as Vanessa cardui . Sometimes good and sometimes bad, the beneficial aspect of a painted lady butterfly is the rapacious appetite of its larvae for Canada thistle. Its larvae also enjoy feeding on soybeans and sunflowers. Downsides include leaving its frass, or poop, behind on canola blooms, which can result in downgrades upon delivery. HOVERFLY: Sometimes called a syrphid, hoverflies are abundant in Canada. A person could be forgiven for thinking they are a wasp, despite their lack of a stinger. They lay eggs directly into aphid colonies and, from birth, the larvae start eating aphids. It happens quick and the hoverfly has perfected this deadly operation. Clockwise from top, a lady beetle snacks on aphids, common green lacewing, T. Julis perches on a cereal leaf beetle. Photos:Ladybeetleand lacewingphotos courtesyofDan Johnson, T. Julis courtesyof EmilyLemke.