AMARILLO – Dr. Don Henne is taking the opposite flight of the potato psyllid, the insect he’s spent many hours studying in the past two years.
Henne, who has been an assistant research scientist in Dr. Charlie Rush’s research plant pathology program with Texas AgriLife Research in Amarillo, will migrate south to take a new position as an assistant professor of vegetable integrated pest management in Weslaco. He will begin this new position on Dec. 1.
Henne will leave his work in Amarillo that has centered on zebra chip disease of potato, a relatively new disease caused by the bacteria Liberibacter solanacearum, which is vectored, or moved from plant to plant, by the potato psyllid, a small gnat-like insect.
His research on zebra chip is part of a large national research program called the Specialty Crops Research Initiative, according to Rush, who leads the research team. The initiative provides funding to a multidisciplinary, multistate team of scientists interested in finding economical and environmentally sustainable ways of reducing losses from the disease that can be easily adopted by potato farmers.
So although Henne is leaving Amarillo, he is not leaving behind the zebra chip initiative or his specific research projects on zebra chip. He will continue working with potato psyllids and the zebra chip issue in the Weslaco area, where it is a major concern.
“We will maintain a collaborative relationship with the scientists in Amarillo, although I will be starting my own research program, where I will be responsible for pest management of insects occurring in such commodities as onions, potatoes and melons,” Henne said.
“There will be a shift in my research focus from epidemiology to pest management so I will be evaluating new insecticide chemistries and integrating them with other methods of control – biological, cultural, mechanical – that we can use on the potato psyllid,” he said. “Growers need to have some idea of systems or ways of managing the potato psyllid other than spraying insecticides.”
In addition to scientists with AgriLife in Amarillo, Henne said he will continue to collaborate with scientists in California and Washington, as they too do a lot of zebra chip projects in Weslaco. In his latest Amarillo research, Henne said his concern was with potato psyllid cold tolerance and its ability to overwinter in the High Plains, another region where there is significant potato production in Texas.
“We’re interested in seeing if they are overwintering in that region and moving into potato plants in the spring,” he said.
In the study, Henne and the team looked at alternate host plants that occur near potato fields. Liberibacter-positive psyllids were placed on a variety of plants to determine what would happen to the plant subsequent to these artificial infestations.
“We found in the case of the wild host plant, wolfberry, which occurs in South Texas, that although the psyllid vector survives very well, the plant was not susceptible to the bacteria,” he said.
“Another wild plant species, buffalobur nightshade, tested positive for the bacteria, but the plant died from the infection. The third species we tested, silver leaf nightshade, was successfully infected with Liberibacter, but appeared to tolerate the infection with no ill effects on the plant itself from either the bacteria or the feeding psyllids.”
After determining that certain plants would act as hosts for both the bacteria and its psyllid vector through the winter, Henne said the study evaluated psyllid cold-tolerance and what temperatures were required to kill potato psyllids, either adults or nymphs.
“What we are finding is temperatures that routinely occur in the Texas High Plains during the winter, which are well below freezing, are insufficient to kill the nymphs, although some of the adults died at these temperatures,” he said.
Henne said he thinks substantial progress has been made on the epidemiology of the potato psyllid thus far.
“We have a pretty good idea of the distribution of the disease in the potato fields – when it appears, how fast it appears and the ultimate fate of the plants themselves. We have a long-term project now to try to correlate the epidemiology with weather parameters.”
With weather stations situated from deep South Texas in Weslaco to Pearsall, Olton and Dalhart, and in other states as well, he said they will use the recordings of different weather parameters – temperature, humidity, wind speed and direction, dew point and solar radiation – to eventually build a model for predicting psyllid outbreaks and risk of zebra chip.