The cotton jassid (a.k.a. twospotted cotton leafhopper), Amrasca biguttula, an invasive pest now widely distributed in Georgia, has a wide host range including a variety of vegetables. While this pest has shown obvious injury in cotton and okra the last few months, damage in other vegetables has been less obvious. Both cotton and okra respond rapidly and severely to infestation with typical “hopperburn” symptoms. In these two crops, leaves of infested plants first yellow, then turn reddish and may include distortion and marginal darkening (burn), and finally will turn brown and may drop. Typical severe symptoms on okra are pictured below.
The other vegetable that is frequently listed as severely impacted by this pest is eggplant. Commercial fields have not shown symptoms (to my knowledge). This is true of many of our vegetables and is likely a result of treatment for whiteflies suppressing jassid populations (more on this below). We have seen symptoms on eggplant, but only in experimental plots which are not being treated for whitefly. These symptoms are much less obvious than those seen in okra. Initially, symptoms were not obvious until adjacent treated and non-treated rows were compared. The plants appeared very similar, but the treated plants readily outgrew the non-treated (picture below; treated plants on the right). Closer examination, well after treatment, showed some discoloration and/or yellowish speckling of lower leaves which eventually developed marginal leaf necrosis. Keep in mind, this was non-treated plants which also had heavy whitefly populations, so we still can’t say for certain this is jassid injury. We are planning current trials to further address this question. Similarly, we have seen squash fields that have shown similar symptoms that appear to be jassid damage (pictured below), but again not definitive due to additional confounding issues in the field.
Why have we not seen more issues with jassids in our vegetable crops? They are present in many of our crops. This may simply be that the jassids don’t harm these other crops (similar to broad mite which has a very wide host range but primarily damages pepper and eggplant). Whiteflies are also likely playing a roll. Where we are fighting whitefly (in most of our vegetable production regions), frequent insecticide applications for whitefly are likely aiding in control of jassids – particularly where neoniotinoids are in the rotation.
There as been a great deal of insecticide efficacy work done on this pest in the last two months – mostly in cotton, but trials in okra and the cotton trials have shown comparable results. Results of foliar applications in okra, as in cotton, has shown initial suppression (particularly of immatures jassids) with most of the neonicotinoids, Beleaf, Torac and Incipio (Incipio not yet registered). Longer residual suppression of hopperburn symptoms was obtained with Venom, Sivanto Prime, Torac, Beleaf and Incipio. In-row drench application (simulating a drip-irrigation chemigation treatment) with systemic insecticides applied over small okra plants also showed excellent efficacy with the neonicotinoid insecticides and Beleaf. While all of the neonic and Beleaf treatments initially suppressed hopperburn symptoms, Venom did provide the longest suppression of these symptoms. Also of note, the treated row in the larger eggplant pictured below showed excellent efficacy with Venom as either a foliar or drench application. The cotton jassid is widespread in southern Georgia (and has even been detected in the Athens area) and in fact has been detected throughout the southeastern US. It is a potential pest of vegetable crops with obvious damage in okra in Georgia and potentially in other crops. The lack of damage in many, or at least some, of our vegetables may well be a result of control obtained by our whitefly treatments. If this pest remains an issue in the fall, it will likely influence insecticide selection in sensitive crops; however, if it appears in damaging numbers in the Spring it may well add a new level of complexity to our insect management programs.
Okra with hopperburn
Eggplant (left row non-treated, right row treated)
Eggplant with suspected jassid injury
Squash with suspected jassid injury
Okra – Foliar efficacy trial – Jassid counts
Okra Foliar trail – hopperburn ratings
Okra drench trail – Jassid counts
Okra drench trail – hopperburn ratings
