Bulb mite

Taxonomic classification: Caloglyphus spinitarsus belongs to the order Acariformes and the family Acaridae. It is a soil-dwelling mite known as a bulb mite, which typically feeds on decaying organic matter but can cause significant damage to living plant tissues under favorable environmental conditions.

Host crops: This pest has a wide range of hosts, primarily affecting bulbous plants. It commonly attacks onions, garlic, shallots, carrots, and potatoes. Furthermore, Caloglyphus spinitarsus is a major threat in greenhouse cultivation, targeting flowering bulbs like tulips, lilies, and hyacinths both in the field and during storage.

Biology and life cycle: These mites thrive in moist, organic-rich soil. Their life cycle consists of several stages: egg, larva, protonymph, deutonymph (hypopus), tritonymph, and adult. The hypopus stage is particularly important as it facilitates dispersal to new host plants. Rapid reproduction allows for several generations to occur within a single season, especially in humid conditions.

Damage and severity: The mites invade bulbs and roots, usually entering through the basal plate. As they feed, they create tunnels that serve as entry points for bacterial and fungal pathogens, leading to bulb rot. Symptoms include stunted plant growth, yellowing foliage, and complete collapse of the root system. Infested bulbs in storage often turn into a soft, putrid mass.

Control measures: Management of Caloglyphus spinitarsus relies on preventive and cultural practices:

• Maintaining dry and cool storage conditions for harvested bulbs.
• Ensuring proper crop rotation to break the pest's life cycle.
• Rigorous sorting of planting material to ensure only healthy bulbs are used.
• Improving soil drainage to reduce the moisture content that mites prefer.
• Applying recommended acaricides if infestation levels exceed economic damage thresholds.