Flea beetles are a common pest of many vegetable crops, including radishes. Flea beetles are small jumping beetles that feed on the leaves of plants, leaving small holes that can eventually kill the plant. They are particularly attracted to young, tender plants and can cause significant damage in a short amount of time.
Flea beetles typically overwinter in plant debris or soil and emerge in the spring to feed on young plants. They are known to be attracted to certain plants, such as radishes, and can quickly establish populations in the field.
Flea Beetles Management in Radish
The Life Cycle of Flea Beetles
- The four lifecycle phases of fleas are egg, larva, pupa, and adult.
- Both men and females mature for reproduction after their first blood meal.
- About 50% of flea populations are eggs, followed by 35% larvae, 10% pupae, and 5% adults.
- Eggs can be deposited on a host or substrate and hatch in two days or two weeks.
- Larvae can develop in 4 to 18 days and eat organic substances.
- Pupae create silken cocoons that they can later fashion into adult forms when vibrations, heat, and carbon dioxide are present.
- Fleas can produce 5000 or more eggs during their two to three-month lifespan as adults.
- The ideal temperature and humidity for the flea life cycle are 21 to 30 °C and 70 %, respectively.
Factors Favoring Population Increase in Flea Beetles in the Field
- In leaf litter, hedgerows, windbreaks, and wooded regions, flea beetles spend the winter as adults.
- Early spring is when adult flea beetles become active and deposit one or more eggs in small crevices in the soil or on the leaves of various ornamental, edible, and flowering plants.
- The roots of recently planted seedlings are consumed by the tiny white larvae that emerge from the eggs.
- Flea beetles usually have one to two generations per year.
Identification of Flea Beetles in the Radish Field
- Except for the spinach flea beetle, which is 1/4 inch long, most mature flea beetles are tiny (1/16 to/8 inch long).
- Flea beetles come in various colors, including metallic gray, blue, brown, black, copper, and striped varieties.
- Large hind legs are used for jumping by flea beetles, particularly when they are disturbed.
- They can seriously harm harvests because they feed on plant leaves.
- Larvae can be seen eating plant roots.
Damage Symptoms of Flea Beetles in Radish Field
- Small, round holes in the leaves: Flea beetles feed on the leaves of radish plants, causing small, round holes that can be seen on the surface of the leaves.
- Shothole appearance: The feeding damage caused by flea beetles can create a shothole appearance on the leaves.
- Stunted growth: If flea beetle populations are high, they can cause stunted growth in the radish plants.
- Wilting: Severe flea beetle damage can cause the radish plants to wilt and eventually die.
- Defoliation: In severe cases, flea beetles can defoliate radish plants by feeding on most foliage, reducing yields and crop losses.
- Flea beetle larvae: Flea beetles also have larvae that can feed on the roots of radish plants, causing damage and reducing the plant’s ability to take up nutrients.