How Can I Control Citrus Leafminers?

Do you want to control scales using traps?

Do you want to control scales using the biological control method?

Do you want to control scales using the cultural control method?

Do you want to control scales using the physical control method?

Traps baited with a pheromone are a useful tool for detecting leafminers, determining when moths are flying and depositing eggs, and timing insecticide applications. However, they do not catch enough of the population to be used for control. Only male moths are drawn to the pheromone and become caught in the trap's sticky coating. Hang pheromone traps about shoulder height on a citrus tree. Follow the manufacturer's recommendations for maintaining the trap, such as how often the pheromone dispenser should be replaced. Commercial traps specific to citrus leafminer will attract only citrus leafminer, but other insects may accidentally be caught in the trap.

Citrus leafminers are killed by various parasites and predators, including tiny non-stinging, naturally occurring wasps such as Cirrospilus and Pnigalio species. The parasites lay their eggs inside the mine, inside or on top of the leafminer larva. When the parasite egg hatches the parasite larva consumes the leafminer larva. These parasites are very important for reducing citrus leafminer levels. Do not spray citrus with broad-spectrum insecticides and avoid other practices that disrupt natural enemies whenever possible.

Citrus leafminer moths are attracted to the new flush of citrus trees. Avoid pruning live branches more than once a year, so that the cycles of flushing are uniform and short. Once the leaves harden, the pest will not be able to mine the leaves. Do not prune off leaves damaged by citrus leafminer since undamaged areas of leaves continue to produce food for the tree. Do not apply nitrogen fertilizer at times of the year when leafminer populations are high and flush growth will be severely damaged, such as in the summer and fall.

Vigorous shoots known as water sprouts often develop on branches and above the graft union on the trunk of mature trees. These shoots grow rapidly and produce new leaves for a prolonged period. Where citrus leafminer is a problem, remove water sprouts that might act as a site for the moths to lay eggs. Suckers, the vigorous shoots which grow from the trunk below the graft union, should always be removed since they originate from the rootstock and do not usually produce desirable fruit.

Many insecticides registered for residential use do not effectively control citrus leafminers, because they have difficulty reaching the larvae inside the mines. Leafminer infestations on mature trees rarely if ever require insecticide treatment. If very young or high-value trees are infested, insecticides can be applied to the new foliage when egglaying moths are active or to the soil in advance of new flush growth. Imidacloprid applied to the ground at the base of citrus trees provides the longest period of control, 1 to 3 months. Imidacloprid should only be applied once a year. Imidacloprid applications should be timed to protect periods of leaf flushing, such as in the spring and fall.