Photo: Randy Lemmon
Most of the questions I get regarding citrus leaf miners usually start off in one of two ways:
- The leaves on my citrus are shriveling up and have some squiggly lines embedded in them.
- The leaves on my citrus are curling up and have shiny little trails on them.
As a solution, a homemade regimen was concocted, and I can assure you it works. Simply alternate neem oil and spinosad. Once I saw the first infestation of leaf miners on one of my satsumas, I started the simple weekly control on all my citrus trees (lemon, lime, and satsumas), and I haven't had a problem since.
Spray with one, wait a week to 10 days, and spray with the other.
Here are some thoughts regarding the use of these two products and controlling leaf miners in general:
- One you start the alternation of neem and spinosad, you must CONTINUE the process on a weekly or every-other-week basis.
- You can stop applications once temperatures go below 85 degrees for an extended period. In Houston, this is typically from November through March.
- Despite the warning on spinosad labels, you CAN use it more than three times in a season, because you are alternating the controls - not just using spinosad.
- The alternating of controls keeps the insects from getting used to one insecticide.
- Neem oil and spinosad are both organically derived products and safe for fruit-bearing crops. There are no known "systemic" chemical controls for citrus trees.
- The moths, which lay the leaf miners, love new growth. Thus, new growth needs the treatment.
- While they can make a leaf turn "ugly," leaf miners are not life-threatening. These insects are relatively new to the Houston area — the problem originated in Florida in 1993 and came to Texas around 1995.
- Highly infected leaves can be pinched off.
- Curled-up leaves are often an additional sign of leaf miners. Spread the leaf out to be certain and look for "snack trails."
- You can find neem oil in most garden centers, but spinosad is most often found in independent nurseries and garden centers rather than at "big-box" stores and mass merchandisers.
- If you don't have an infestation, it has been noted that you can use these two as a preventive, on a 10-14 day basis.