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Sawflies



P_sawfly

Sawflies

Usually appear in

Spring to Autumn.


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Caused By:-     Various Sawflies

Description

The Blackheaded Ash Sawfly Tethida barda Adult and larvae. Picture by David Cappaert, Michigan State University and Lacy L. Hyche, Auburn University, Bugwood.org.
Sawfly is the common name for insects belonging to suborder Symphyta of the order Hymenoptera, which also includes bees, wasps and ants. There are hundreds of sawfly species around the world most of which are specific to a particular plant specie.
See these sawflies Apple, Aquilegia, Geranium, Geum, Goosberry, Iris, Large Rose, Plum, Rose Leaf-rolling, Solomom Seal.
As with with most Hymenoptera, adult sawflies have two pairs of wings but can be distinguished by the lack of a narrow constriction between the thorax and the abdomen.
Although a few Sawflies are carnivorous and eat other insects, the adults tend to feed on the pollen and nectar and there is a vast range of colours and shape. They can be as small as 4mm and as large as 40mm. Some mimic flies, wasps and other beneficial insects.
The name Sawfly is given because of the saw like egg depositor appendages the females have, which they use to cut into the plant stems or leaves to lay their eggs.
The problem is with the larvae of the Sawfly which eat the leaves of various plants and trees. Large populations of certain sawfly species can cause substantial damage to forests and cultivated plants. Although some larvae feed on the open leaves many feed in between the leaves epidermis.
The feeding activities of the larvae can induce leaf rolling or gall formation on some plants.
Sawfly larvae usually look like caterpillars, but some look like little slugs. You can tell them apart by looking at the number of abdominal pro-legs of the larvae. Slugs don't pro-legs, caterpillars have five pairs of feet at the second part of the body after the first three insect legs, while the larvae of sawflies have a minimum of six.
Leaves that become skeletonised or transparent with just their veins remaining tend to be the work of sawflies, which eat through the leaf tissue until it has almost completely disappeared.
After growing to full size most sawfly larvae pupates in the soil.
The website provided on Malcolm Storey's extremely useful BioImages (UK) website: http://www.bioimages.org.uk/Index.HTM shows many sawflies.


Control

Picking the larvae by hand can be done if the infestation is not great.
The lifecycle of the Sawfly can be broken at two times. First, in late winter and early Spring, gently loosen and turn the soil around the base of the tree with a trowel or hoe. This will expose the over-wintering pupae for birds to eat.
The second action is to spray the tree with a suitable insecticide as soon as possible after the eggs have hatched. Repeat spraying may be necessary.
Continued vigilance is necessary as the sawflies are difficult to catch laying eggs.
One organic way to prevent attack is to spray the bush with a soup made by pouring hot water over foxgloves leaves.


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