Ask the Master Gardeners: July 2013
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July 1, 2013 | 1442 views | Post a comment
Q: Some of the leaves on my red oak are skeletonized -- the green tissue is gone and the veins remain with kind of a brown part of the leaf remaining. What did it and what do I need to do now?
A: Skeletonizers can be caterpillars or slug sawflies. Caterpillar damage is cosmetic according to the Missouri Botanical Garden website. By the time you find the damage, it is too late to control (bacillus thuringiensis would be the proper spray). Oak slug sawfly also skeletonizes leaves. The United States Forest Service says that microbial diseases and other natural enemies usually keep the sawfly in check. However, if too much of the tree is covered, then you can spray with insecticidal soap (according to the Ohio State University site) or spinosad (the Better Homes and Gardens site).
Q: What is the webbing on the trunk of my oak tree?
A: Barklice are beneficial insects that eat fungi, algae, dead bark and other organic materials on tree trunks and large limbs. If the webbing really disturbs you, you could wash it off with a high pressure hose. However, if you leave the web alone, the insects and the webbing will slowly disappear. One Internet article says that the insects eat the web before the end of the year; another, that the webs disintegrate as they weather.
Q: When do I plant my winter garden?
A: There is a rule of thumb for planting vegetables that will freeze. (This includes cucumbers, squash, tomatoes, cantaloupe, eggplant, okra, peppers, pumpkins, watermelon, etc.) First, take the number of days from seeding or transplanting to harvest. For a Celebrity tomato, that would be 70 days. Then add two weeks or 14 days for the "fall factor." Things grow slower in the fall. Add 3 weeks or 21 days for frost tender plants which would include the tomato. Here we have 105 days. This is how many days to count back from our first frost date. Of course, the "first frost date" is the problem. For San Antonio it is around November 28. In 2010 near Seguin (my house) the first freeze was November 27. In 2011 the first freeze at my house was November 4. In 2012 my first freeze was December 11. Using the November 27 date, we count back 105 days and come up with August 15 as the last possible time to plant the tomato. However, counting back from November 4, we end up having to plant the tomato by July 23. From this, you can see, first of all, that I keep a garden journal, and second, that it is hard to guess the weather. Plant early, shade the plant from afternoon sun, and be prepared to protect from freezes.
Or, just plant fall vegetables. These include beets, broccoli, Brussels sprouts, cabbage, carrots, cauliflower, Swiss chard, collards, kohlrabi, leeks, lettuce, mustard, onions, peas, potatoes, radishes, spinach and turnips. This past year was my best year ever for beets and leeks (lots of frozen leeks for soup, and many jars of pickled beets).
Clara Mae Marcotte is a Texas Master Gardener with Texas A&M AgriLife Extension. If you have a question to be answered, call the Master Gardeners at 830-379-1972 or leave a message to be answered. The website is guadalupecountymastergardeners.org. The Master Gardener research library is open Mondays from 8:30 to noon, on the second floor of the Texas A&M AgriLife Extension building, 210 East Live Oak in Seguin.