Wash the Spider Out


The eensy weensy spider climbed up the water spout.
Down came the rain and washed the spider out.
Out came the sun and dried up all the rain.
Then the eensy weensy spider climbed up the spout again.

That’s exactly what we don’t want. London needs some rain to wash the spiders out. More specifically, the spider mites.

Not sure if you have noticed, but we could certainly use some rain in London, Ontario. While there was plenty of rainfall back in March, precipitation levels have been far below average since then. Don’t get me wrong. The sunshine and warm temperatures are great after a cool spring, but when you look around, everything is starting to look pretty dry. Lawns are already starting to go dormant and the calendar has only just flipped over to June!

Precipitation Data from London International Airport – 2016
Month Average Precipitation (mm)+ Actual Precipitation (mm)^
January 74 49.6
February 60 76.8
March 78 141.6
April 82 48.6
May 83 31.1
June 87 0.2*
Total 464 347.9
* actual precipitation as of June 2, 2016
^ historical data from Environment Canada
+ statistical data from Weather Network

London has received 100+ mm less precipitation than average totals so far in 2016. And that’s not good. Dry lawns are one thing, but far more is affected by drought than that. As you might have guessed, area trees are starting to show signs of stress.

In deciduous trees, stress can be seen in leaves which droop, yellow, dry out, or drop off trees. Coniferous trees in stress are less obvious to spot, but are affected just as much during periods of drought. All trees become more susceptible to disease and insect infestation when exposed to long periods of stress. And CLC has seen evidence of that already.

With periods of hot, dry temperatures like what we’ve seen in London over the last little while, it’s no wonder that spider mites are on the rise. Spider mites thrive in hot climates and happily attack houseplants, tender annuals, and crops. They don’t stop there though. Sadly, CLC Tree Services has noticed spider mite presences in area coniferous trees.

Female of the red form of the spider mite Tetranychus urticae with two silk wires. The substartum is a bean leaf. Scale : mite body length ~0.5 mm Technical settings : - focus stack of 39 images - microscope objective (Nikon achromatic 10x 160/0.25) on bellow

Spider mite | By Gilles San Martin – originally posted to Flickr as Tetranychus urticae with silk threads, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=11208762

While spider mites are less than a millimetre in size, the damage they can incur is far larger. They quietly swing into gardens and trees on the wind and take up residence on host plants. After spinning protective silky webs, they munch on leaves or needles for a few days. Eggs are then laid, which can hatch in as little as 3 days. Within 5 days, the spider mites reach the adult stage and the process starts all over again. With the potential of hundreds of eggs being laid over the course of a few weeks, you can begin to see where the problem lies.

For coniferous trees, that problem is exasperated by the fact that when spider mites strip the tree of its needles, they do not come back. If a deciduous tree is healthy, and treatment is sought, it may grow new leaves that season, or at the very least, have a chance to recover in future years. Once an evergreen loses its needles though, the damage is permanent.

Don't Forget to Water Your Trees!

Water your trees! A hydrated tree is a healthier tree

So what can you do about spider mites? Start by getting out and watering your trees. Stressed trees are susceptible trees and, with the lack of rain in London, area trees are under stress. If you see signs of spider mites though, you need to begin treatment as early as possible. On annual plants and deciduous trees, you can prune out affected leaves, stems or branches. Insecticidal soap is another option. It sticks to limbs and reduce numbers, but the problem is that insecticidal soaps also reduce the number of beneficial insects—ladybugs, lacewings, predatory mites—which naturally help to reduce the presence of spider mites. Because of the short life cycle of spider mites, three applications are necessary. And if it comes down to losing your tree, sometimes that is your only option.

If you are worried that your coniferous tree is affected by spider mites, contact CLC Tree Services. We can assess your trees and offer treatment for trees up to 30 feet high. But until Mother Nature sends some much-needed rain our way, do your trees a favour and get out and water them. A hydrated tree is a healthier tree, and sometimes that makes all the difference.

Published by
June 3, 2016 3:17 pm