Description. The adult fleahopper is about 1/8 inch long and pale green and have sucking mouthparts. It is flat with an elongated, oval outline and prominent antennae. The body usually is yellowish-green, although it may be white or yellow with minute black hairs and spots on the upper surface. Nymphs resemble adults but lack wings and are initially almost white in color or sometimes pinkish. After feeding, the immature stage is pale green with prominent, often reddish eyes. Other parts of the body also may be reddish. Nymphs sometimes can be confused with immature minute pirate bugs, big-eyedbugs, aphids, and lygus. But differences in color, shape, behavioral patterns, etc. can be used to distinguish these from cotton fleahopper.
Although cotton fleahoppers are considered a pest in early squaring cotton, they’re ecological role in later cotton is not certain, but they are currently not considered pests beyond first bloom. Cotton fleahoppers are omnivorous, meaning they feed on plant tissue and other insects as well, particularily the eggs of bollworms and other lepidopterous pests.
The cotton fleahopper overwinters in the egg stage, primarily in wild hosts such as woolly croton (Croton capitatus), horsemint (Monarda citriodora), cutleaf evening primrose (Oenothera laciniata), showy sundrops (Oenothera speciosa), wooly tidestromia (Tidestromia lanaginosa), spotted [horsemint] beebalm (Monarda punctata), lemon [horsemint] beebalm (Monarda citriodora) and silverleaf nightshade (Solanum elaeagnifolium).
The eggs are about 1/30 of an inch long and are inserted under the bark of small stems. At 80° F., eggs hatch in about 11 days, and the young nymphs feed on tender vegetation. They usually molt five times and require 14 to 15 days to mature into the reproductive adult cotton fleahopper. Usually there are six to eight generations per year. Of these, only one to three occur in the cotton field. Early in the spring, fleahoppers build up large numbers on alternate weed hosts. As these hosts mature and become less succulent, the cotton fleahopper searches for more preferred hosts. If cotton is present, fleahoppers colonize in it and feed on leaf and fruit buds. Fleahoppers can often be found in large number in cotton fields well into boll development and beyond cutout.
Damage. Both adults and nymphs suck sap from the tender portion of the plant, including small squares. Pinhead size and smaller squares are most susceptible to damage. The cotton fleahopper feeds on anthers of the small squares and sucks sap from leaf buds. This feeding causes squares to die and turn brown, resulting in a “blasted” appearance. When fleahoppers are abundant, heavy fruit loss may occur on preflowering plants. Cotton is primarily susceptible to cotton fleahopper damage during the first 3 weeks of squaring. The cotton fleahopper prefers terminal bud clusters including young leaves and tiny squares. The piercing, sucking habit of nymphs and adults interferes with normal growth patterns in cotton. Feeding punctures stimulate the plant to produce shorter main stem internodes, more nodes and spindly branches or “suckers” from the lower parts of the plant. The fleahopper injects saliva when feeding, but its effects are only local. There is no evidence that fleahoppers transmit plant diseases or toxic substances other than digestive enzymes.
Given sufficient time, cotton is often able to compensate for lost squares with little impact on yield, particularly those lost during the first week of squaring in the more southern areas of the state. However, under conditions where the cotton is planted late, and/or the growing season is significantly shortened by cool temperatures, compensation maybe less likely or lint quality may be adversely affected.
Management and decision making.
Cultural management. Managing weedy hosts around cotton fields my help reduce the source for cotton fleahoppers. Late planted fields are often the targets of fleahopper infestations that developed in earlier planted fields. If weed hosts are eliminated by spraying or mowing, fleahoppers may be forced into adjacent cotton resulting in a spike in fleahopper damage. Some cotton cultivars are more attractive to fleahoppers or are more susceptible to their damage than others.
Biological control. Although there is not much information available regarding the role predators and parasitoids play in reducing cotton fleahopper numbers, they undoubtedly have an impact; particularly on source populations developing on weedy hosts.
Scouting. As the first small squares appear (approximately 4- to 6-leaf stage), examine the main stem terminal buds (about 3 to 4 inches of plant top) of 25 plants at each of at least four locations across the field. More sites should be sampled in fields larger than 80 acres. Some varieties, primarily older varieties, will begin squaring as low as the 5th node while most newer varieties may not start fruiting until the 7th or 8th node. Fields should be scouted for cotton fleahoppers weekly. If conditions are conducive to the rapid build up of cotton fleahoppers in alternate hosts, scouting intervals should be shortened (i.e., monitor fields every 3 to 4 days). Count the number of adult and immature cotton fleahoppers encountered. Cotton fleahopper can be extremely “flighty”, and will often fly or hide within the plant canopy when disturbed. When approaching a plant to sample, watch for adults flying from the plant. Grasp the plant at about the middle of the main stem to help prevent nymphs from moving from the terminal toward the lower canopy before you have time to inspect the terminal.
Under windy conditions fleahoppers may take refuge within the plant canopy and thus easily missed if sampling only terminals. Under these conditions it may be beneficial to perform whole plant inspections, but keep in mind that the action threshold is based on terminal counts and a whole plant inspection threshold does not currently exist.
Chemical control and Action thresholds. The action threshold for cotton fleahoppers varies depending on the region of Texas. Make certain to follow the guidelines for your region (see regions map on page ??). When considering an insecticide application be cognizant that as plants increase in size and fruit load, larger numbers of fleahoppers may be tolerated without yield reduction. When plants are blooming, fleahopper control is rarely justified. In addition, insecticides applied early in the blooming period may result in outbreaks of aphids, bollworms and tobacco budworms because of the destruction of predaceous insects and spiders. The later the insecticide application is relation to week of squaring and planting date, the more important is to avoid using broad-spectrum insecticides to manage cotton fleahoppers. If making an insecticide application during the 3rd week of squaring, and/or to late-planted cotton, a less disruptive, “soft” insecticide may be the best choice.
High Plains, Rolling Plains and Trans-Pecos areas.
In these areas the cotton fleahopper action threshold is based on the number of cotton fleahoppers counted and the amount of squares the plant is retaining, it is necessary to estimate the percent square set for the field. The use of a plant mapping program such as COTMAN is a good tool for monitoring squaring progress. But any plant mapping technique will work. While all squaring positions can be monitored, focus only on first position squares. A square in this position is produced about every 3-4 days depending on temperature and other environmental factors. When monitoring plants for square set, look for squares all the way up to the highest curled up, mainstem leaf. This leaf should be associated with a pinhead size square. Larger leaves will have larger squares and represent older squares that were previously vulnerable to fleahopper damage and shedding. Also look for scars indicating that a square was shed. Large scars would indicate the shedding of a large square, not due to fleahopper feeding. There are a number of environmental factors that may cause square shed. Record number of first position fruiting positions and the number still with squares. This will provide square set information.
|Cotton Fleahopper Action Thresholds|
|Region||Fleahoppers||Cotton growth stage|
|Blacklands||10-15 per 100 terminals||During the first 3 weeks of squaring|
|Coastal Bend||15-25 per 100 terminals|
|Lower Rio Grande Valley|
|Panhandle||25-30 per 100 terminals with:||Week of squaring||Square set|
|South Plains||1st week||< 90%|
|Permian Basin||2nd week||< 85%|
|Rolling Plains||3rd week||< 75%|
|Trans Pecos||After 1st bloom treatment is rarely justified|
All other regions. In areas outside the High Plains, Rolling Plains and Trans-Pecos regions, the action threshold for cotton fleahoppers is based solely on the number of insects encountered in the plant terminal during the first 3 weeks of squaring.
|Suggested Insecticides and Rates for Managing Cotton Fleahoppers in Cotton
ingredient per acre
|Amount of formulated
|Acres treated per gal or lb of
|Mode of Action Group (IRAC)|
(Orthene 97, Acephate 90, generics)
|0.067||4 fl oz||32||4A|
(Bidrin 8 )
|0.2||3.2 fl oz||40||1B|
(Trimax Pro 4.44, generics)
|0.043-0.06||1.25-1.8 fl oz||102.4-71.1||4A|
1rates will vary depending on product and formulation.