Conventional insecticides such as malathion are also effective. Tips on getting rid of sawfly larvae on roses Originally published July 21, 2010 at 7:00 pm Updated July 21, 2010 at 9:01 pm Start with compost to plant iris. Please check out our sawfly larvae control products for more details about how they work and how, when, where they should be applied. Larvae usually feed for about four to five weeks before pupating in the soil. They must be properly identified because most of the methods used to get rid of caterpillars don’t work on them.. Help with identification can be found at Wildlife Insight.Some families have larvae that are … Bt (Bacillus thuringiensis), which is an effective natural control for true caterpillars, is ineffective on sawfly larvae. To get rid of the sawfly’s larvae, you can spray it on the plants’ ground, and you will notice quick results. Safer ® Brand offers a variety of sawfly larvae control products to help control and eliminate this garden pest and revive your plants. The natural insecticide spinosad will control sawfly larvae. Three species commonly appear on rose plants: the rose slug (Endelomyia aethiops), the curled rose slug sawfly (Allantus cinctus) and the bristly rose slug (Cladius difformis). Kaolin clay acts as a repellent that is capable of eliminating any insects. – Use kaolin clay: This clay serves as a natural barrier if you use it around your plants. Sawfly larvae look similar to caterpillars but are an entirely different kind of insect. Infestations of sawfly larvae often defoliate plants although infestations are usually localised and rarely devastating. The best time to control sawflies is early in their larval stage. Sawfly larvae resemble pesky caterpillars, and they are often mistaken for them by gardeners. This control also repels the adult sawfly and many other insects. Adult sawflies have yellowish-green bodies that reach 1/4 to 3/4 inch in length, while the larvae have 1/2- to 3/4-inch long, yellow-green bodies, yellow to yellowish-orange heads and several caterpillar-like legs. Sawflies are related to bees and wasps and belong to the order Hymenoptera.Like caterpillars, sawfly larvae usually feed on plant foliage, but unlike most caterpillars sawfly larvae can quickly destroy a rose garden or defoliate an entire tree.