What Insecticides Control Apple Sawfly Larvae
Apples are a favorite fruit that is enjoyed by many. Although apples are mostly eaten during the morning hours ( breakfast time) these fruits can be eaten any time of the day even as a midnight snack. Fill with nutrients apples are one of the healthiest fruit that’s consumed, in fact, the statement “an apple a day keeps the doctor away” shows that we should make this fruit a part of our daily diet.
Research has shown that there are 7, 500 varieties of apples that are grown worldwide, and 1oo varieties of apples are grown commercially in the United States. History records that the apple tree originated in Kazakhstan, in central Asia east of the Caspian Sea. Alma Ata, capital of Kazakhstan, by 1500 BC apple seeds had been carried throughout Europe.
Etruscans and Romans cultivated apples as well, during the early centuries of the Christian era, apple seeds, and trees were reportedly carried to the British Isles. The apple tree has a very rich history and has been cultivated from humble beginnings. However, in this article, we will be discussing the apple sawfly. This insect pest has done damage to apple crop growers and apple trees that are grown in the home garden. We will be discussing the biology, the damage, and the control of these insect pests.
Identifying the Adult Apple Sawfly and the Larvae or Maggots
The adult apple sawfly measures 4-5 mm long the insect’s head and thorax are blackish brown the abdomen is brown and the legs are orange-brown. The larva is whitish in color with a brown head capsule and 10 pairs of legs.
Dogwood Apple Sawfly Biology
- The adult sawfly emerges on sunny days when the apple tree starts to blossom
- Once mating is completed the eggs are deposited or laid singly in the side of the receptacle of the apple flowers throughout the blossom period
- In about a week or two the eggs are laid
- During colder weather, however, the eggs will take longer to hatch
- Once the eggs hatch the young larva burrows into the receptacle, often just beneath the skin where characteristic ribbon scars appear
- Once the larva reaches semi-maturity it often moves to another fruitlet, boring into the ovary and feeding on the pips
- On being fully fed in late June or early July the larvae then enter the soil where they form a cocoon, at a depth of 25 cm
- During the winter months, the larvae will overwinter in the cocoon before pupating 3-4 weeks before emerging the following spring
Signs of the Apple Sawfly Damage
- In late May and June, fruitless that are affected have holes that are obvious with the larva’s blackish-brown excrements spilling out
- Affected fruitless often drop off the tree, as the part of the June drop, this loss of fruit is small
- Early Larva feeding leaves brown spiral scars on the skin of the apple. After a while, more serious damage consists of larval tunneling and exiting holes from which flows reddish brown frass with a strong odor. The larva will enter more than one fruit, frequently leaving frass-covered entry holes, the loss of the hole cluster can occur
- Fruitlets that suffer only initial feeding by a damaged sawfly larva can remain and develop as fruits The fruits are usually misshapen and have a long ribbon-like scar, about 4mm wide. Often starting at the eye end of the fruit and extending around the circumference. The fruit in some cases is still edible
How do You Get Rid of Apple Sawfly?
There are many ways to bring apple sawflies under control. We will start with the non-chemical methods first because chemicals can kill non-targeted (beneficial insects) insects. Also, the wrong use or overuse of chemicals can encourage food contamination.
- Encourage predators and other enemies of the apple sawfly maggots into your garden, for example, ground beetles, parasitic wasps, birds, ants, and spiders,
- It’s been recommended to wash the apple tree with a tree wash once the season ends. This tree wash will remove debris and dirt which overwintering pests use as a harbourage
- Remove damaged fruitlets to prevent insects from moving on to other fruitlets or going into the soil to pupate
- Where the population is at an acceptable level will not cause severe damage
- Using an apple sawfly trap will not only trap them but allow you to monitor them as well
- Grease bands for fruit trees clear bands will prevent the insect from climbing the tree in the spring after they have overwinter
- Soon after pollination is completed apply effective insecticides that are recommended. Insecticides should also be rotated to reduce the chance of resistance development in pests
The final word on apple sawfly control
The apple sawfly can be a nuisance by destroying apple crops. The good news is these pests can be brought under control, all it takes is some know-how and with this guide, you will have much success as you reap a harvest of healthy crops.
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About the author
Norman loves being in the garden, both at home and for his job....
he is 'Natures Little helper' being outdoors, growing his vegetables and flowers from an early age.
Now having spent over 22 years in the profession he want to give some of his knowledge to others...
his vast array of hints and tips you will find scattered over this site will help you no end growing plants in your garden.
I know that this is about sawfly larvae but I’m currently in an area where there is a fungus thats attacking box woods and I have no clue what to do! Do you know anything that could help? Normally I would just take them out but literally 3/4 of my plants are box woods and they are all around my house! So what do I do?
Hello so happy to help and so sorry to hear about your boxwood, there are many products to try for example.
chlorothalonil or chlorothalonil mixed with thiophanate methyl hope this helps.