Ponderosa Pines

Ponderosa Pines

The sawfly is eating ponderosa pines again in 2015 in Colorado. In 2014 there was a problem with sawfly infestations in our area. Being in the Parker Colorado area, you need to be on alert for how this pest may affect your property. This year Elbert County and southeast of Denver, Colorado is rearing another sawfly outbreak which may also spread.

What is a Pine Sawfly?

Adult Female Sawfly

A sawfly is a brown wasp and it is spreading through Colorado. The “saw” part of its name reflects the saw appearance the female sawflies use to cut plants and lay eggs in pine trees. The image on the left is an adult female sawfly (Photo: USDA). The adult sawfly is stingless and does not harm humans. The sawfly larva has a similar look to caterpillars and eats leaves of ponderosa pine evergreen trees.

Adult Male Sawfly

The sawfly wasp to the right (Photo: Wikipedia) has already been ravenously eating ponderosa pines across thousands of acres just southeast of the Denver area and the sawfly outbreak in Elbert County is likely to have more repercussions according to the Colorado State Forest Service. State entomologist Dan West states, “Three years of this insect feeding on ponderosa pine trees can cause the trees to die”.

How Do Sawflies Change Ponderosa Pine Trees

Sawfly on Ponderosa Pine

The photo on the left is a Colorado State Extension Program image of an evergreen tree that has been infested with sawflies. The sawfly eats the needles of the ponderosa pine. Normal ponderosa pine trees are the trees we traditionally see in our homes as Christmas trees. After a sawfly infestation, pine trees will look more sparse like the look in the photo to the left. The larvae will eat on pines generally in the summertime, from March on the Ponderosa to later on other types of pine trees. Although the larvae appear to look like caterpillars, they are not caterpillars and will not be affected by treatments usually effective on caterpillars. The type of insecticide, when to apply it, and how well it is applied are all important for the treatment to be effective. Be sure to hire a trustworthy, professional arborist to get the job done right. With 20 years in the business, we are here to help with any tree issues. To receive a free estimate, please complete this contact form.

Should We Be Concerned about Sawfly Infestations?

According to Colorado State Extension Program, “Light populations may not cause serious damage, but moderate to heavy populations can significantly impact tree health. When sawfly larvae are present in high numbers, sprays are justified to protect tree health.” If you are in need of tree spraying, we have over 20 years of experience in this field. We will come to inspect your ponderosa pine tree’s health or to address any tree concerns. ArborScape services is a fully licensed, insured business with licensed arborists who have the training to legally handle the treatments effective for infestations.

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2 thoughts on “Ponderosa Pines

  • We have about 50 trees infected and all our neighbors too. What can we do? Who do recommend spraying or what can we buy to kill these pests?

    1. Thank you for your question, George and Darlene. To treat the pine sawfly infestation properly and thoroughly, it is best to hire a professional to manage the problem for you. Our licensed and insured professional tree service will be happy to give you a free estimate and treatment options. Please complete this short form and we will help you within one to five business days.


      Thank you and please let me know if you have any other questions!

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