Q. My 30 foot tall live oak tree is covered with aphids.
Should you spray now or will the aphids die if the weather gets cold?
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| Aphids on southern Live Oak |
A. Aphids overwinter at the base of trees and weeds
nearby. Their populations are much smaller, but they are there. Eliminate weeds
and apply “dormant oil” to the tree twice; once in December and again in
January before new growth begins.
nearby. Their populations are much smaller, but they are there. Eliminate weeds
and apply “dormant oil” to the tree twice; once in December and again in
January before new growth begins.
Dormant oil is a holdover name from decades ago when
forms of this oil were safe to apply only during the winter. You might find
this product now with names like horticultural oil, superior oil, supreme oil
and others.
forms of this oil were safe to apply only during the winter. You might find
this product now with names like horticultural oil, superior oil, supreme oil
and others.
 |
| Oil for spraying in a pint container. This company has chosen to call it a horticultural oil. |
These newer oils are different. These are not vegetable
oil or neem oil used as insecticides but a different type of oil that
“smothers” overwintering bugs. I have used these newer oils in the fall, spring
and even early summer months as long as the plants are not flowering.
oil or neem oil used as insecticides but a different type of oil that
“smothers” overwintering bugs. I have used these newer oils in the fall, spring
and even early summer months as long as the plants are not flowering.
 |
| This oil for commercial use is in 2 1/2 gallon container. This company chose to call it Ultra Pure Oil |
Ants and aphids rely on each other. Controlling ants helps
control the spread of aphids and keeps them in check. Controlling ants when
aphids are problems is an important component when controlling aphids. I like
to use ant bait products like Amdro applied exactly as the label says.
control the spread of aphids and keeps them in check. Controlling ants when
aphids are problems is an important component when controlling aphids. I like
to use ant bait products like Amdro applied exactly as the label says.
 |
| One of the ant baits supplied by Amdro |
Don’t worry about small
numbers of aphids on trees if you eliminated weeds and controlled their ant
buddies. Leave them alone unless there is some problem you can’t live with. If the
ant problem is intolerable, apply soap sprays, neem oil or a systemic
insecticide if it’s a bad problem. But don’t go in that direction unless you must.