Citrus Flat Mite (Brevipalpus lewisi) – A Threat to Citrus and Grapevines

The citrus flat mite (Brevipalpus lewisi) is a serious pest affecting citrus, grapes, and various ornamental plants. It causes economic losses by damaging fruits, reducing their quality, and in some cases, killing young shoots. This pest is widely distributed, with major infestations reported in Japan, Bulgaria, and the desert regions of California and Arizona.

Life Cycle of Citrus Flat Mite

1. Eggs – Laid in depressions on fruit surfaces, cracks, or hollow cavities in leaves.
2. Larva – Hatches 8 to 16 days after being laid.
3. Protonymph – An active stage in the mite's development.
4. Deutonymph – Another active stage before adulthood.
5. Adult – A small, flat mite, typically amber-colored with black pigmentation.

Factors Affecting Life Cycle

• Temperature – Developmental rates increase with temperature.
• Rainfall – Dry conditions make mites more virulent.
• Host Plant – The number of generations per year depends on the type of host plant.

Damage to Plants

• The mites feed by inserting their mouthparts into plant tissue and injecting toxic saliva.
• Their feeding leads to scarring of citrus fruits, reducing market value.
• They are also vectors for several plant viruses.

Temperature & Humidity Preferences

• Optimal Temperature – Around 32.2°C (90°F).
• Low Humidity Preference – The mites thrive in dry conditions with 35% relative humidity.
• High Temperature Impact – Increases development speed and population growth.

Control Measures

• Monitoring mite populations in citrus and grape plantations.
• Removing alternative host plants near citrus orchards.
• Using biological control agents or selective pesticides when necessary.

Effective management is crucial to minimizing the damage caused by Brevipalpus lewisi and ensuring healthy citrus and grape production.

Source: Plantwise and UCIPM