Pine Sawfly Control

Pine Sawflies Control Methods

Sawflies Quick facts

Pine Sawfly Control-a-pine-tree
A Pine Tree
  • There are 8,000 recorded sawfly species
  • Identifying the pine sawfly is important because the larvae resemble butterflies and moth caterpillars
  • Sawflies are common insect pests that invade gardens and landscapes feeding on many shrubs, trees, and grasses Some species also feed on cereal crops
  • Sawflies do not affect a plant’s health ( shrubs & trees) only the appearance
  • There are many best practices and pesticides to protect shrubs and trees from sawflies
  • The ideal time to treat sawflies is at the larvae stage since pesticides have no real affect on adults
  • Sawflies emerge in late  spring and start to feed on the new plant growth
  • Some species emerge early in the spring before new growth on trees has occurred and eat older needles  from previvous years
  • A few species eat both  new and old foliage, this group of species can completely strip conifers trees in a single season

How to Identify the Adult Pine Sawfly & Larvae

Pine sawflies are relatives to the bees and the wasp, these garden pests are non-stinging insects. The color of the adult female pine sawfly varies from light to dark brown with yellow-red-white markings. The pine sawfly does damage by feeding on the epidermal cells.

When this happens this causes the leaves to lose moisture which leads to needles drying out along with being twisted and turning brown,  the female measures in length 8 to 10 mm and possesses a stout and thick-waisted body and narrow antennae can be found on the head, and there are also two sets of wings clear to light brown with prominent veins. The length of a male pine sawfly measures 5 to 7 mm with a slender thick-waisted body, black to brown colored wings with broad feathery antennae thats on the head. The pine sawfly larvae have a black head and legs with a body that’s gray-green and off-white stripe can be seen positioned down the middle of the back and stripes that are lighter on both sides.

Pine Sawflies Biology

The female sawfly lays about six to eight eggs in 12 pine needles each, the following year, April through May the eggs hatch. The larvae feed until-mid June, and the larvae congregate in colonies. 10 to 100 of these larvae or caterpillars can be found feeding on the pine needle, because of their tiny mouth part the caterpillars rasp off the epidermal cells. The older larvae however eat the entire needle from the tip to the base.

Signs of the Pine Sawflies Damage

Look for these signs of pine sawfly damage.

  • Look for sawfly frass or excrement below the infested tree
  • Spotted needles contain the sawfly’s eggs
  • Branches also miss needles
  • Look for needles that are brown or tan along with being curled

How to Manage and Control the Pine Sawflies

There are many ways to manage the pine sawflies that will bring control.

1. Proper Maintenance Practices: Poor soils along with drought will encourage the presence of sawflies, keeping your trees well watered along with the right fertilizer program will encourage a healthy tree that can stand up against pine sawflies.

2. Mechanical Control: An effective way to control sawflies is by mechanical control, this method involves several practices, if the infestation is small then the larva can be hand-picked and thrown into a bucket of soapy water. If overwintering eggs are discovered can be pulled off the tree placed in plastic bags and discarded. If the infestation is small simply pruning that part placing it in a plastic bag and properly discarding will bring control. The larvae can be knocked off the tree and crushed.

3. Natural or Biological Control: Rodents will eat the pupae that are found in the soil, and native birds find these caterpillars to be a delicacy. Several parasites have been introduced to control these caterpillars

4. Insecticides: Insecticides should be the last resort and should only be considered when the pine sawfly population is high or has reached an unacceptable

level. Before applying insecticides read and follow the manufacturer’s directions for the best results. Here are some insecticides that will bring complete control, these insecticides are most effective against the larvae stage, Insecticidal soaps, Horticultural oils, Bi–Neem, Sevin, Acephate, Carbarly, etc…

Note: Keep all insecticides stored in a safe ventilated place out of the reach of kids and pets.

The final word on pine sawfly control

The pine sawfly like other sawfly species can be controlled, it is a matter of identification, knowing their biology along with putting the right control measures in place depending on the level of infestation that will bring success. This guide will help you to eliminate these garden pests so your pine trees can continue to grow healthy while they retain their beauty. So follow this guide and see for yourself, you will be happy with the results.


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About the author

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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.

2 thoughts on “Pine Sawfly Control”

  1. Impressive and comprehensive article, Norman! Your detailed insights into the pine sawfly’s biology, identification, and control measures are invaluable for anyone dealing with these pests. It’s clear that you’ve put a lot of research and effort into creating this guide. The methods outlined seem practical and easy to follow.

    Is there a specific time of day that is most effective for treating pine sawflies, especially when utilizing insecticides or other control measures? Would treating them during certain times increase the success rate?
    Thanks, Lou.


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