Rose Sawfly/Rose Slug
Irregular holes and the skeletonization of rose leaves indicates rose slug damage, also referred to as rose sawfly. The larva resemble tiny yellowish-green larvae and they feed on the green leaf tissue inbetween the veins. Eggs are deposited on leaf undersides. To prevent and control infestations, in mid spring inspect both leaf surfaces. Remove infested leaves or for more severe infestations spray with a forceful spray of water or use soap, horticultural oil and water or neem oil.
In May and June tiny, pale green worm-type larvae, with a brown head will start feeding on rose foliage. Pale tan blotches soon appear n the leaf surface. The larvae eat the green tissue on the leaf undersides so the leaf has an appearance of irregular windowpanes. Soon all that’s left are the veins; the leaf’s skeleton.
Adult sawflies and ¼ inch long and resemble a black wasp. Females deposit the eggs into the leaf edges. The eggs hatch in mid-April to early May. They first feed on the leaf undersides between the leaf veins. As they mature they go through numerous larval states until they fall to the ground. They then wrap themselves into a cocoon for protection as they pupate into adults. They overwinter in their cocoons then emerge as adults and to mate. Once they mate they deposit their eggs on leaf edges and they process continues. Luckily there is only one generation per year. The adults don’t feed on the foliage, only the larvae does.
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Control of rose Sawflies
Although the larvae damage is unsightly, it doesn’t kill the plants. Start inspecting the underside of rose leaves in mid-April. The easiest and quickest way to kill these pests is to pick them off, squish them or put them in a container of soapy water, or even rubbing alcohol. The larva feed for about a month, so be patient.
For infestations where picking them off an option, spray them off with a forceful stream of water. You can also use with soap and water, neem oil or horticultural oil. Coat the plant and ground thoroughly. Repeat spraying are needed, every seven days, but do inspect daily and remove any lingering larva.
For infestations where picking them off an option, spray them off with a forceful stream of water. You can also use with soap and water, neem oil or horticultural oil. Coat the plant and ground thoroughly. Repeat spraying are needed, every seven days, but do inspect daily and remove any lingering larva.
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