Beautiful gardens by William Johnson
HERE ARE four questions for the dog days of August.
Q: Help! My satsuma tree has a heavy load of fruits but many of their rinds suddenly started to split one day recently. What caused this and what can I
do about it?
A: After weeks and weeks of ample rainfall over the spring growing season, we entered into an extended period of drought conditions as early summer arrived.
The day following the first rainstorm that broke the drought a few weeks ago,
I started receiving inquiries about the cause of citrus fruit splitting. This type of damage typically occurs when citrus trees rapidly take up water from rain or irrigation after a long dry period. The fruit expands and bursts the peel in a crack across the bottom or blossom end of the fruit.
The buildup of excess fluids produces sufficient internal pressure to cause
the skin to burst. Young trees have the highest incidence of splitting, which occurs commonly on oranges, mandarins and tangelos. In contrast, grapefruits are rarely affected.
Maintaining adequate and even soil moisture levels by regular irrigation during extended periods of dry weather is the best defense against fruit splitting.
Q: The trunk of my pecan tree has several horizontal bands. Each band consists of a series of small holes evenly spaced up and down and around the trunk. It looks like someone used a drill
to make the holes. What caused them?
A: Several phone calls to my office this month were questions on the cause of a horizontal series of holes appearing on the trunk or branches of pecan trees.
The holes are spaced rather uniformly in distinctive rows around the trunk or even the tree’s major branches, with each hole being about the diameter
of a pencil and only about
a quarter-inch or so deep.
These holes are made by a woodpecker called the yellow-bellied sapsucker. At least two reasons are provided in literature for why this particular woodpecker does this.
One is that the birds peck out holes to consume the sap and, indeed, they might show a preference for one tree in the yard and ignore another of the same species right next to it. In fact, these birds will return again and again to the same tree.
The other reason is that the yellow-bellied sapsucker pecks out the holes for the apparent purpose of providing a place for insects
to hide. The bird then supposedly returns periodically to eat the insects that seek refuge there.
In general, sapsuckers rarely cause serious damage to trees because the holes they peck are shallow.
Pecans are not the only trees affected by these woodpeckers, as oaks and other home-landscape trees are also frequent targets of the birds’ insect-mining efforts. If the holes had been random in occurrence, then the likely culprits would have been insect pests known as tree borers.
Q: I have small yellow insects crawling on my cucumber plants. Are they harmful and, if so, how can I control them?
A: The insects are most likely cucumber beetles, which are lime yellow with black spots.
They look somewhat like – and are often confused with – lady beetles but with longer bodies.
The most commonly occurring species of cucumber beetle in the county is known as the spotted cucumber beetle, which has 12 spots distributed over its body.
Cucumber beetles chew
on the young stems and leaves of cucumbers, cantaloupe, squash, pumpkins, watermelons, beans, peas and even okra, causing poor growth and yield.
You can spray insecticides such as Ortho’s Bug-B-Gon Lawn and Garden Insect Killer that contain esfenvalerate as the active ingredient on many of the vegetables mentioned. Check the insecticide’s label for specific directions.
Q: How often do daylilies need dividing? What is the best technique to use?
A: You should divide your daylilies every three to five years, depending on how crowded the plants are and whether flower production is declining.
Division is best done
in early spring, as new shoots begin to emerge,
or in the fall after the plants become dormant.
While most daylily varieties are quite tough,
I think it is beneficial to wait until lower fall temperatures prevail to dig them out. When dividing overcrowded plants, dig the whole clump.
Separate a clump’s plants by using two spading forks inserted back to back into the middle of the clump and then prying it apart. This is less damaging to the roots than cutting, which injures a large number of the plant’s feeder roots.
Cut the foliage back to about four inches from the ground.
If you are going to replant in the same location, first replenish the soil with well-rotted compost and a fertilizer high in phosphorus for root development. You may plant larger daylily varieties up to 30 inches apart and smaller varieties as close as 12 inches.
William Johnson is a horticulturist with the Galveston County office of Texas A&M AgriLife Extension Service. Visit his website at aggie-horticulture.tamu.edu/galveston/index.htm.
Many home citrus growers have reported that the rinds of their maturing citrus fruit started splitting soon after plentiful rainfall ended the summer drought. This type of damage typically occurs when citrus trees rapidly take up water from rain or irrigation after an extended period of dry weather.
PHOTO CREDIT: William Johnson