Feature

Outbreaks of the broad-headed bug Esperanza texana

By C.S. Clem, K. Kesheimer, and D.W. Held

This odd story begins with email or text messages from consultants, landscape managers, and agrochemical distributors about outbreaks of small bugs (they meant true bugs or hemipterans) in bermudagrass and zoysiagrass lawns. These were mostly accounts from the southern half of Alabama in 2019 with one or two incidents around Birmingham in 2015 and 2017. In most cases, there were no insects to identify, or quality pictures useful for an identification of the insects. The small sap-sucking bugs were guilty by association with damage to turfgrass. The persons on site were certain that these outbreaks and the associated damage were not caused by chinch bugs, but it may have been damage from two-lined spittle bugs. The pests implicated with this damage were from a little-known family of true bugs, Alydidae (the broad-headed bugs). The insects that have been confirmed were the adult stages of Esperanza texana (sorry, no common name). This brownish colored, elongated sap sucking insect is approximately 5 mm (0.2 inch) long with elongated antennae and a speckled appearance to the body and legs (Figure 1).

FIGURE 1. An adult Esperanza texana. The brown coloration with a speckled appearance to the narrow body, and a head wider than the body distinguishes E. texana from other sap sucking true bugs in turfgrass. Photo by C.S. Clem.

What do we know? Esperanza texana is not a new invasive species, but it is possible humans have contributed to an expansion of its natural range. Collection records from TX to SC and FL go back to the early to mid-1900’s, but it was not documented in AL until relatively recently by Dr. Charles Ray of Auburn University. Dr. Ray and Dr. Clem published an inventory of Alabama broad-headed bugs in 2016. By examining 550 museum specimens and insects from field collections, they concluded there are eight species in six genera in the state, with E. texana reported from nine counties. Esperanza texana is a member of the subfamily Micrelytrinae, which also includes two other species in the state, Stenocoris furcifera and Stenocoris tipuloides. These three species feed exclusively on grasses or sedges as host plants. So far, E. texana alone has been associated with turfgrass damage, not the other two. When broad-headed bugs are present in damaged turfgrass, they may co-exist with other sap-sucking insects that also feed on grass, like plant bugs and spittle bugs.

There are records of E. texana occurring in only 11 counties throughout Alabama (nine noted in the previous survey plus Talladega and Jefferson counties). Given the availability of grass and sedge hosts in all counties, E. texana is likely present but undetected throughout Alabama. This year and in previous years, reports of damage to zoysiagrass (Meyer) and bermudagrass have been reported primarily in summer to early fall (most in September). The damage (Figure 2) is not distinct. Infested areas are discolored which could be mistaken for damage from other grass-feeding pests or drought. Damage has been reported in established lawns, not new, and in the literature, populations are also associated with damage to bermudagrass in pastures. Damage is almost exclusively reported in turf exposed to direct sunlight, with one report of spring damage to bermudagrass in a shaded area.

FIGURE 2. Damage associated with populations of adult Esperanza texana. Photo taken by David DeWeese, DeWeese Lawns (Talladega County, AL, Sept 2021), used with permission.

Little is known about the biology of E. texana. Related species with comparable width to length body ratios hide within, and likely feed inside, leaf axils of their grass hosts. Seasonally, a peak of adults in late summer to early fall is consistent with other seasonal observations for the family. In south central Florida, adults have also been reported in mid to late April, suggesting at least two generations per year are possible especially in Mobile and Baldwin counties. Esperanza texana likely overwinters in lawns as adults or eggs.

Records from Auburn University Plant Diagnostic Clinics suggest 2017 was the last year when outbreaks of E. texana occurred. It is plausible that weather or rainfall patterns could drive these outbreaks. Both 2017 and 2021 had similarly high rainfall amounts in June. Because we lack details on the biology or life history, the influence of weather patterns on outbreaks are speculative at best.

Since outbreaks are uncommon, there are no published techniques for sampling or management. Simple sampling techniques used for other turf pests, like sweep nets or direct observations, can also be used to detect E. texana. This should be done on turfgrass areas that are discolored with no other apparent cause. Immature stages do not fly, so samples should be taken in mid-August to prevent populations from building to damaging levels by September. Since this insect does not appear on insecticide labels, landscape managers can only control outbreaks with products that are labeled for a specific site such as lawns or athletic fields. A landscape professional shared that a pyrethroid product labeled for use on turfgrass lawns was effective to reduce populations.

In summary, outbreaks of adult Esperanza texana, a sap sucking broadheaded true bug have occurred sporadically in AL since 2015. These outbreaks are typically in September and may be more abundant in years with above average summer rains. The limited information on the biology and management of E. texana have enabled high populations to cause damage in zoysia and bermudagrass lawns. Outbreaks may be an annual occurrence which suggests sampling in August is the best recommendation to detect populations before they peak and cause damage.