Cotton

Not known to transmit any human or animal pathogens.

Not known to vector any pathogens or other associated organisms.

Visual surveys and using tools such as sweep nets and beat sheets on potential hosts are the only methods to detect CSB because there are no trap options for this species. There are no CSB-specific pheromone lures or traps available for surveys or population reduction and there are no non-specific traps that capture this species.

Host plants with brown leaves and stipple marks from feeding. Note: This type of feeding damage is not specific to CSB, but it can help to identify an area for survey.

Shriveled and discolored seeds inside cotton bolls. This can be a difficult symptom to find because the cotton plants show no external signs of damage.

Aggregations of adults and nymph-stage CSB. These insects commonly group in tight clusters, especially in seed pods or bolls. CSB resemble fleas in infested bolls. Look for small black or brown bugs running through the cotton.

Aggregations of CSB produce a pungent odor and crushed CSB stain the lint of cotton pinkish.

Surveys should take place primarily during the breeding period when seed bolls are open. The breeding period occurs between late spring and early fall (Kirkpatrick, 1923). The timing and seasonality of the breeding period may vary depending on location and climate.

During the breeding period, search for CSB on open cotton bolls (Derksen et al., 2010). Bolls typically open as early as July, and CSB will remain on the plant until harvest in October (Cotton Counts, 2010). Most bugs are found within the bolls, but they are found occasionally in leaf litter or on the leaves of cotton plants (Smith and Brambila, 2008).

Surveying during the quiescent period (from fall until early spring) is not recommended due to the cryptic nature of CSB. During this time, CSB stops feeding and begins aggregating in old bolls or other hidden areas.

The survey should take place during a time when infestation is most apparent. In general, this means CSB surveys should occur during the breeding period, when hosts (predominantly from the Malvales order) are producing fruits, seeds, and seed pods. Surveyors may find CSB populations more easily after seed bolls are open or after a recent rain (Adu-Mensah and Kumar, 1977; Ismail, 2018).

Adult CSBs can be difficult to visually detect from a distance because they are small (less than a ¼ inch) and darkly colored (Samy, 1969). Surveys are most effective when host plants are sampled individually or inspected to find insects hiding in the bolls or on the plant. CSB will emerge when the boll is agitated.

For surveys during the quiescent period (NOT recommended), surveyors can search for CSB in sheltered areas near host plants. CSB can be found in leaf litter beneath cotton plants (Smith and Brambila, 2008), but the bugs appear to prefer aggregating on trees and will use any sheltered area to overwinter.

Colonies aggregating on trees may be detected near the ground, up to a height of more than 20 feet (Kirkpatrick, 1923). CSB has been observed on various species of Ficus, Acacia, and some Eucalyptus, suggesting that rough barked trees are more attractive than smooth barked trees (Kirkpatrick, 1923; Shah et al., 2016).

Aggregations have also been observed in stored cotton, in hedges near cotton fields, on the undersides of leaves and plant pods, on dried flower heads, underneath maize and sugarcane fodder, in abandoned paper wasp nests, in the cracks of telephone poles and fenceposts, and in artificial traps such as old sacks (Adu-Mensah and Kumar, 1977; Kirkpatrick, 1923).

CSB surveys can occur wherever host plants are present. This includes many environments, from residential gardens and ornamental plantings to agricultural fields growing cotton. The hibernation sites used by CSB during the quiescent period are so varied that it is not efficient to survey for CSB when cotton bolls and Malvales seeds are not present (Sharma et al., 2010).

The most suitable method for detecting and delimiting CSB in the field is through visual inspection. Conduct visual inspections by searching for life stages of CSB and damage symptoms. Cotton plants, other potential malvaceous host plants, and nearby resting places for aggregations of CSB can be inspected.

Carefully inspect the newly matured bolls and dry seeds to locate CSB. High density infestations are obvious. Cotton seed bugs resemble fleas in infested bolls; look for small black, grey, or brown bugs running through the cotton. Open bolls into a plastic zipper storage bag and spray them gently with a small amount of 70% alcohol (isopropyl works, but ethanol is recommended) from a spray bottle or atomizer (a perfume atomizer purchased at the local dollar store works nicely). Close the bag quickly. The alcohol will irritate CSB, which will quickly become very active. This technique promptly indicates an infested boll. Since this is a quarantine pest in the United States, do not open the bag; instead freeze the sample and then pick out the bugs (Sharma et al., 2010). Individual CSBs can be stored in the freezer or placed in a vial of 95% ethanol to preserve them for later identification.

Morphological examination of adults is needed to confirm identification. See Brambila (2020) for the field screening aid and Samy (1969) for the full dichotomous key. Final identification by an expert can be made by observation of the male genitalia and the externally visible parts of the parameres but may require dissection and examination of adult male internal structures (See Notes in this section).

Brambila (2020) is the field screening aid for O. hyalinipennis.

Samy (1969) is the most comprehensive identification key to species of Oxycarenus and focuses on those present in Africa.

Péricart (1998) is an identification key for the species occurring in France.

Not present in the U.S.: Oxycarenus albidipennis, O. bokalae, O. congoensis, and O. pallidipennis. O. hyalinipennis can be differentiated from O. boklae by examining the clavus which will be either completely or mostly pale, brick-red to white, whereas in O. bokalae the clavus will be almost uniformly dark brown or black (Slater et al., 1994). O. albidipennis, O. pallidipennis, and O. congoensis can be differentiated by their orange-red coloration of the first five abdominal segments (Slater et al., 1994).

The keys of Samy (1969) and Péricart (1998) rely primarily on externally visible characters including the number of spines on the profemur, coloration of the body, wings, and antennae, and shape of the opening of the male pygofer (or genital capsule). In the field, a surveyor can make a preliminary identification using external characters. However, to make a final identification, examination of the male genitalia including the shape of the pygofer opening (visible without dissection) and the externally visible parts of the parameres is likely necessary. In some cases, a final identification may require dissection and observation of the internal parts of the male genitalia, including the subgenital plates and remaining parts of the parameres.