1) Fig. 1: Eggs are oblong, approximately 1.0 mm in length, and creamy-white.
2) Fig. 2: Adults are shiny black, and about 9 mm in length with a reddish head.
3) Fig. 3: Adult males tend to be smaller than adult females.
4) Fig. 4: Adults feed on the upper and lower leaf surfaces causing leaf skeletonization.
5) Fig. 5: Severe damage to plants reduces aesthetic quality and marketability.
The redheaded flea beetle, Systena frontalis, has emerged as a major insect pest in nursery production systems. Adults feed on many different ornamental plants; however, based on our experience and feedback from producers, Itea sp., Hydrangea sp., Cornus sp., and Weigela sp., are highly susceptible to redheaded flea beetle adults. In fact, specific cultivars tend to be more susceptible, including Itea
The life cycle of the redheaded flea beetle consists of an egg, larva, pupa, and adult.
Eggs are oblong, approximately 1.0 mm in length, and creamy-white (Figure 1). Larvae are 5-10 mm long, creamy white, and have a brown head capsule when mature. The last body segment has a fleshy projection that curves upward, with hairs on the end. There are three larval instars. Larvae are located
Adults are shiny black, and about 9 mm in length with a reddish head (Figures 2 and 3). Adult males tend to be smaller than adult females. Females lay eggs individually. Adults possess an enlarged hind femur that allows them to jump/hop similar to a flea—hence the common name. Adults feed on the upper and lower leaf surfaces causing leaf skeletonization and creating holes in leaves (Figures 4 through 6). In addition, adults deposit black fecal material on leaves during feeding.
Weed removal from within the nursery, including containers, will help reduce potential food sources of redheaded flea beetle adults. Redheaded flea beetle adults may enter nurseries from surrounding vegetation; especially if the plants or weeds are a viable host. It is important to develop and implement an aggressive scouting program by monitoring for adults weekly, focusing on plants that are highly susceptible to redheaded flea beetle adults, and then conducting spray applications accordingly. Apply insecticides weekly when adults are active. We have found, in our efficacy trials, the following insecticides to be effective in protecting plants from damage caused by redheaded flea beetle adults: acetamiprid (TriStar), dinotefuran (Safari), and cyfluthrin (Tempo). Thorough coverage of all plants is important, as well as, the growing medium/soil as redheaded flea beetle adults may be able to sense changes in air pressure. Consequently, the adults will hop off plant leaves and land on the surface of the growing medium/soil (Figure 9) or the leaves of adjacent plants. Systemic insecticides can be used; however, adults still have to feed on plant leaves to be negatively affected, and depending on numbers, may still cause substantial aesthetic damage.