Troubleshooting Curling Leaves and Poor Fruit Set on a Potted Bearss Lime Tree

I'm growing a Bearss lime tree in a large container in Southern California. It produced fruit reliably for four years, but this season the new growth is severely curling and coated with a clear, thin, plastic-like film. The older leaves look fine, but every new leaf emerges distorted. The tree also hasn't set any fruit since this growth appeared. I don't see any obvious insects besides occasional spider webs. I've been watering more frequently lately—possibly too much—and there's been an unusual number of dead bees in the neighborhood. What could be causing this?

Diagnosis: Citrus Leafminer Damage

The curling and silvery "plastic" coating on your new leaves are classic signs of citrus leafminer (Phyllocnistis citrella) infestation. The larvae tunnel inside the leaf tissue, creating serpentine mines that cause the leaf to curl and develop a silvery, reflective appearance as the epidermis separates. This pest primarily targets tender new growth, which explains why mature leaves are unaffected.

Leafminer activity typically peaks during warm weather and declines as temperatures cool. In Southern California, the pest often goes dormant in winter, allowing the next flush of growth to emerge clean. While the damage looks alarming, established trees generally tolerate it well without long-term harm.

Fruit Production Issues

The lack of fruit set is likely unrelated to the leafminer. Citrus trees need consistent, deep watering to bloom and hold fruit—aim for at least 3 inches of water per week during the growing season, applied slowly to penetrate the entire root zone. Overwatering in a container can be just as damaging as underwatering, leading to root rot. Ensure your pot has excellent drainage and allow the top few inches of soil to dry between waterings.

Regarding the dead bees: this is a separate environmental concern and won't affect your lime's pollination. Citrus flowers are self-fertile and also attract other pollinators like hoverflies, native bees, and even wind can transfer pollen.

Management Recommendations

• Leafminer: No treatment is strictly necessary. The damage is cosmetic. If desired, horticultural oil or spinosad applied to new flushes can reduce mining, but timing is critical.
• Watering: Water deeply when the top 2–3 inches of soil are dry. Avoid frequent shallow watering.
• Fertilizing: Feed with a citrus-specific fertilizer according to label directions to support healthy growth and fruiting.
• Monitor: Watch for other pests like scale or aphids, which can cause sooty mold (black coating) rather than the silvery film you're seeing.

With proper watering and patience, your lime tree should recover and produce a good crop next season.