Gardening
for Your Watershed – September
2004
---------------------------------------------------------------------------
Topics in this issue:
- Garden Journals
- Pest of the Month: Fall Webworm
- Landscaper Checklist
---------------------------------------------------------------------------
Garden Journals
---------------------------------------------------------------------------
A garden journal can be a great tool for tracking pest infestations, plant health, and fertilizer and water use. If you don’t already keep a garden journal, now might be a good time to start. The gardening successes of this season are still fresh in your mind, as are ideas for changes next year.
A journal can be as simple or as fancy as you want to make it. Some people use a notebook or a three-ring binder with loose-leaf paper; others go out and buy pre-printed journals with inspirational quotes and specific categories for observations. It can also involve as much or as little effort as you like; avid gardeners may make daily entries, while others are content with weekly, bi-weekly, or monthly notes.
Most general journals include items such as first and last frost date, planting dates, species names, flowering and harvest dates, and so on. For a watershed-friendly gardening journal, you may want to jot down the following observations about your garden for each entry:
- Water use. What has the recent precipitation been like? How much have you been irrigating, and what methods have you tried (drip irrigation, watering by hand, etc.)? How are your plants responding? Remember that too much water can be as bad for some plants as too little.
- Pest management. What plants seem to attract the most pests? How much damage is the plant taking, and is it affecting the entire plant?
- Beneficial insects. Which plants do honeybees and other pollinators like the best? Do you see them more often at certain points in the season?
- Plant rotation. What plants are in which spots? Tracking and rotating locations over the years can help to reduce soil depletion and pest outbreaks.
- Fertilizer use. When have you used fertilizer, how much did you use, and on which plants? What effects have you noticed, and how long has it been since the application?
You may also want to paste in photos and/or sketches. What do your plants look like during a hot spell, a wet season, several weeks after fertilization, or during a pest outbreak? Comparing their conditions over two or more seasons can help you make decisions about when to water, fertilize, or manage pests.
---------------------------------------------------------------------------
Pest of the Month: Fall Webworm
---------------------------------------------------------------------------
Seeing some large wads of webs on the tips of your trees? In the spring
and early summer, your trees are likely playing host to tent caterpillars,
but at this time of year, it’s more likely to be fall webworm (Hyphantria
cunea), a native of North America.
Fall webworm only feeds on deciduous trees, not conifers, with a special taste for alder, willow, cottonwood, and fruit trees. Masses of eggs—400-500 in each batch—laid on the underside of leaves hatch into caterpillars with long white hairs in June or July.
As with tent caterpillars, fall webworms congregate together and build “tents” out of webs; unlike their cousins, fall webworms don’t venture out to forage, but eat the leaves underneath the tents. When they’ve eaten a patch bare, they’ll enlarge the nest into new territory. The larger the tent, the older the colony. Usually a single-season infestation won’t do much long-term damage to a tree, although repeated infestations year after year will weaken a tree.
If you decide to control for fall webworm, the best time to do it is when webs are small, before the caterpillars have matured enough to pupate. If the webs are low enough to be reached, the easiest way to control them is to cut off branches with tents and drop them into a bucket of soapy water. For webs that are higher up, try poking a stick or pole with a nail inserted crosswise at the end into the web. Twist the stick to get the web to wrap around it, and you’ll be able to pull most of it down.
For heavy infestations, you may want to try the biological insecticide Bacillus thuringiensis (commonly known as B.t.). Apply it to the leaves outside of the web; when the caterpillars expand their tent, B.t. will be ready and waiting for them. Or, since B.t. is short lived, try shredding the tent a little so B.t. can penetrate the web.
To prevent problems next season, thoroughly rake leaves out from under the tree after they’ve all fallen, as webworms often overwinter in leaf litter. If you see their dark brown cocoons, don’t compost the leaves.
-----------------------------------------------------------------------------
Landscaper Checklist
-----------------------------------------------------------------------------
Wondering what to look for in a landscape maintenance company? See this
checklist of what a watershed-friendly landscaper
should be doing.
-----------------------------------------------------------------------------
For more watershed-friendly gardening tips, visit http://lakewhatcom.wsu.edu/gardenkit.
=============================
This newsletter
is produced by Whatcom County Extension. To subscribe or unsubscribe,
or to make comments and suggestions, please contact Scarlet
Tang or
360/676-6736.
