|Armstrong, John - Scott|
|Medrano, Enrique - Gino|
Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Experiment Station
Publication Acceptance Date: 2/1/2012
Publication Date: 2/12/2012
Citation: Brewer, M., Armstrong, J.S., Villanueva, R., Biles, S., Medrano, E.G., Esquivel, J.F. 2012. Verde plant bug is associated with cottong boll rot in South Texas cotton. National Cotton Council Beltwide Cotton Conference. 13302. Interpretive Summary: Plant bugs and stink bugs are traditionally referred to as sucking bugs, and they have reached elevated past status in cotton. Insecticide sprays, which traditionally controlled these sucking bugs have been reduced following the introduction of transgenic Bt-cotton for worm control and boll weevil eradication. Sucking bug feeding occurs on reproductive tissue of cotton, and for many species economic damage primarily occurs from feeding on young to mid-sized bolls. Of the sucking bugs, stink bugs have been shown to cause boll abscission, lint staining and loss, and seed loss. Loss is magnified when bacteria causing cotton boll rot are introduced during feeding, as shown for the southern green stink bug (Medrano et al. 2007). Several species of brown and green stink bugs occur along the Coastal Bend cotton growing region of South Texas, and their abundance and damage potential is variable throughout the region, justifying the need for good in-season monitoring of the complex (Hopkins et al.2009).
Technical Abstract: Verde plant bug was the dominant boll-feeding sucking bug species (>98% of insects collected using a beat bucket) from peak to late bloom in cotton fields near the coast along the Coastal Bend of South Texas, from Port Lavaca to the Lower Rio qrande Valley in 2010 and 2011. It was common in fields within 8 km of coastal waters (average of 0.42 bugs per plant during peak to late bloom), while it was not detected in inland fields. Cotton boll rot was found on up to 25% of the open bolls inspected, the disease was concentrated in coastal fields where verde plant bug was found, and it was the major contributor to boll damage. Results from field surveys and verde plant bug feeding on caged plants supported the positive association of verde plant bug presence and subsequent harvest-relevant cotton boll rot in open bolls at harvest. Based on our findings, we recommend in-season monitoring of verde plant bug to aid in assessing the likelihood of subsequent boll damage from cotton boll rot, especially for fields close to coastal waters. Additional inspection of signs of internal feeding by cracking green bolls(no greater than quarter-sized bolls) may be useful to verify that feeding is occurring in the soft tissue inside the boll, but we caution that inspection for early signs of cotton boll rot in green bolls may be a poor indicator of final disease expression and resulting boll damage. Based on our work, in-season monitoring of the verde plant bug using the beat bucket is currently the best indicator of harvest damage caused by these bugs and potentially magnified by cotton boll rot.