The Eastern Tent Caterpillar has a well earned reputation for being terribly destructive. Capable of leaving entire trees in their wake, this caterpillar has the ability to defoliate a mature tree in a matter of weeks. As destructive as they are, keeping Tent Caterpillars at bay may be easier than you first think.
Where do Tent Caterpillars come from
Tent Caterpillars lay their eggs in the fall usually on smaller branches or in the crotch in between branches. Their eggs are all laid in one general area and can blend in rather well with the tree bark. The untrained observer can easily miss the egg mass, but upon closer inspection a clear bulge if easy to detect.
Eggs laid during the previous fall over winter and begin to awake in mid to early spring. Hundreds of caterpillars can stay in one ‘tent’ for about 2 months. This is the stage where they will do their most damage.
As the caterpillars grow they feast on your tree leaves. How your tree comes back from a tent caterpillar infestation varies greatly on the size of the tree and the amount of caterpillars in the tent. Yet another reason to keep a watchful on your fruit trees. A quick morning or evening walk through your trees once or twice a week will keep you aware of any orchard pests.
When to Look for Tent Caterpillars
Timing is key when it comes to Tent Caterpillars. Removing them by hand is the easiest and most efficient approach provided you catch them at the right stage. Another advantage of monitoring your trees by walking around them every so often, yes even in the winter.
Late fall to early spring is the time to be looking for tent caterpillar egg mass. Eggs are laid in bulk in and around the crotch of a tree branch. The egg mass is hidden in plain sight. Often overlooked at this stage, the egg sack can look like a swollen branch. However a careful inspection usually catches the egg sack.
If you fail to catch the tent caterpillar eggs before the hatch it’s okay. There is still time to catch them pretty easily. Tent Caterpillars are actually easier to spot during this stage of their life cycle.
Early to mid summer is when your tent caterpillar problem can become pretty obvious. If you fail to notice the large spider web like tent, hopefully you will notice all your trees leaves disappearing.
Once you realize you have a caterpillar infestation it’s best to plan a solution. Getting rid of tent Caterpillars is very satisfying and a little gross all wrapped into one.
How to Remove Tent Caterpillars
How you remove your tent caterpillars depends on when you catch them. The beauty of their removal is that you can usually get rid of 99% of them in one shot.
Removing the egg mass is as simple as pruning off the affected branches. After pruning you have two options: throw away the branches or burn them. If you decide to burn them make sure the egg mass burns in it’s entirety. Keep the fire going to a little bit longer just to make sure.
If the egg sack is in a spot where it is impossible to prune out there is another way. Using any hard tool that won’t dig into the tree bark, scrape the egg mass off the branch. Take extra caution to not scrape off the tree bark.
While it’s okay if you scrape a little bark, it’s best to do this removal carefully as to not damage the tree. Hardier, older trees will heal faster than younger trees. Avoid using a knife or other metal tools to do the scraping. A knife can be used to cut into the mass. Then use something soft, yet rigid like a credit card to finish the job. Once removed, discard the egg mass in the trash or burn immediately.
Removing tent caterpillars in the summer while there is an active “tent” is a little more tricky. In the summer caterpillars are most active in the morning and evening when it’s cooler. Usually coming back to the tent during mid day when the temperature rises. Extremely hot or rainy days will keep the caterpillars in their tent as well.
Choose a hot day when the caterpillars have gone back into their tent. Removing the tent can be as simple as pruning out the affected branches. Again be sure to dispose or burn the tent. There can be hundreds of caterpillars in each tent so be careful not to damage the tent when pruning off branches.
If you choose to throw the tent in the garbage double bag the tent. Tie both bags down tight, making sure the branches didn’t puncture the bag.
Burning tent caterpillars is the more immediate way to dispose of the caterpillars. Have your fire burning before you prune off the tent. Upon pruning bring the tent to the fire and carefully place the tent into the center of the fire. A well established fire should do the trick in a matter of moments.
Yes, it looks cool to light them on fire while they are still in the tree. This isn’t the most effective method of removal and can have the opposite results. Taking a torch or similar directly to the tent can further injure an already defoliated tree. Additionally, the tent might fall and hundreds of caterpillars can get alway. If this happens you will be fighting tent caterpillars for the next few season.