Carrie H. Wohleb

Association of Potato Psyllid (Bactericera cockerelli; Hemiptera: Triozidae) with Lycium spp. (Solanaceae) in Potato Growing Regions of Washington, Idaho, and Oregon

Potato psyllid, Bactericera cockerelli (Šulc), causes economic damage to potato crops throughout the major potato growing regions of western North America. When cultivated crops are not available, potato psyllid often occurs on non-crop hosts. In the southern U.S. and northern Mexico, native species of Lycium (Solanaceae) are important non-crop hosts for the psyllid. We determined whether Old World species of Lycium now widespread in the Pacific Northwest are reservoirs of potato psyllid in this growing region. We examined Lycium spp. across a wide geographic region in Washington, Oregon, and Idaho at irregular intervals during three growing seasons. Potato psyllids were present at all locations. To determine whether Lycium is also a host during intervals of the year in which the potato crop is not available, we monitored a subset of these sites over the entire year. Six sites were monitored at 1- to 3-week intervals from June 2014 to June 2016. Psyllids were present on Lycium throughout the year at all sites, including during winter, indicating that Lycium is also a host when the potato crop is seasonally not available. Psyllid populations included a mixture of Northwestern and Western haplotypes. We observed well-defined spring and fall peaks in adult numbers, with peaks separated by long intervals in which psyllid numbers were very low. Seasonal patterns in psyllid numbers on these non-native Lycium hosts were very similar to what has been observed on native Lycium in the desert southwest region of the U.S. Our findings demonstrate that potato psyllid associates with Lycium across a broad geographic region within the Pacific Northwest. These results will assist in predicting sources of potato psyllid colonizing potatoes in this important growing region.ResumenEl psílido de la papa, Bactericera cockerelli (Šulc), causa daño económico a los cultivos de papa a lo largo de las regiones importantes productoras de papa del occidente de Norteamérica. Cuando los cultivos no están disponibles, el psílido de la papa se presenta con frecuencia en hospederos que no son el cultivo. En el sur de Estados Unidos y en el norte de México, especies nativas de Lycium (Solanaceae) son hospederas alternativas importantes para el psílido. Nosotros determinamos si las especies de Lycium del viejo mundo ahora ampliamente dispersas en el pacífico noroccidental son reservorios del psílido de la papa en esta región del cultivo. Examinamos Lycium spp. a lo largo de una amplia región geográfica en Washington, Oregon y Idaho a intervalos irregulares durante tres ciclos de cultivo. Los psílidos de la papa estuvieron presentes en todas las localidades. Para determinar si Lycium también es hospedante durante intervalos del año en los cuales el cultivo de la papa no esta disponible, monitoreamos un subgrupo de estos sitios a lo largo de todo el año. Se monitorearon seis sitios a intervalos de 1 a 3 semanas de junio de 2014 a junio de 2016. Los psílidos estuvieron presentes en Lycium a lo largo de todo el año en todos los sitios, inclusive durante el invierno, indicando que Lycium también es un hospedero cuando el cultivo de papa no esta disponible fuera del ciclo de cultivo. La población de psílidos incluyó una mezcla de haplotipos del noroccidente y del occidente. Observamos picos bien definidos en la primavera y el otoño en número de adultos, con separación de los picos por largos intervalos en los cuales los números de psílidos fueron muy bajos. Los patrones estacionales en números de psílidos en estos hospederos de Lycium no nativos fueron muy similares a lo que se ha observado en Lycium nativo en el desierto de la región suroccidental de los E.U.A. Lo que nosotros encontramos demuestra que el psílido de la papa se asocia con Lycium a lo largo de una amplia región geográfica dentro del pacífico noroccidental. Estos resultados respaldarán en las fuentes de predicción del psílido de la papa colonizando papas en esta región importante del cultivo.

Seasonal Population Dynamics of Three Potato Pests in Washington State

Abstract Pest phenology models allow producers to anticipate pest outbreaks and deploy integrated pest management (IPM) strategies. Phenology models are particularly useful for cropping systems with multiple economically damaging pests throughout a season. Potato (Solanum tuberosum L.) crops of Washington State, USA, are attacked by many insect pests including the potato tuberworm (Phthorimaea operculella Zeller), the beet leafhopper (Circulifer tenellus Baker), and the green peach aphid (Myzus persicae Sulzer). Each of these pests directly damages potato foliage or tubers; C. tenellus and M. persicae also transmit pathogens that can drastically reduce potato yields. We monitored the seasonal population dynamics of these pests by conducting weekly sampling on a network of commercial farms from 2007 to 2014. Using these data, we developed phenology models to characterize the seasonal population dynamics of each pest based on accumulated degree-days (DD). All three pests exhibited consistent population dynamics across seasons that were mediated by temperature. Of the three pests, C. tenellus was generally the first detected in potato crops, with 90% of adults captured by 936 DD. In contrast, populations of P. operculella and M. persicae built up more slowly over the course of the season, with 90% cumulative catch by 1,590 and 2,634 DD, respectively. Understanding these seasonal patterns could help potato producers plan their IPM strategies while allowing them to move away from calendar-based applications of insecticides. More broadly, our results show how long-term monitoring studies that explore dynamics of multiple pest species can aid in developing IPM strategies in crop systems.

New Geographic Records for the Nearctic Psyllid Bactericera maculipennis (Crawford) with Biological Notes and Descriptions of the Egg and Fifth-Instar Nymph (Hemiptera: Psylloidea: Triozidae)

Abstract. The Nearctic psyllid Bactericera maculipennis (Crawford) (Hemiptera: Psylloidea: Triozidae) is one of only five known species of Psylloidea worldwide whose host plants include species of Convolvulaceae (Solanales). Current checklists of North American Psylloidea report B. maculipennis only from California and Utah. Our surveys of field bindweed, Convolvulus arvensis L. (Convolvulaceae), an Old World plant introduced into North America, show that B. maculipennis is considerably more widespread than indicated by historical accounts. We update the psyllids geographic range to include four states (Washington, Idaho, Oregon, Montana) not previously included in contemporary checklists. The egg and fifth instar nymph are described. We provide characters of the egg and nymph that distinguish this species from a congeneric species, Bactericera cockerelli (Šulc), occasionally found on field bindweed. Photographs of the male and female terminalia are provided. Bactericera maculipennis developed successfully on field bindweed and on several species of Ipomoea (Convolvulaceae) in laboratory assays. Overwintering females collected from leaf litter and dead or dormant stems of C. arvensis at locations in Central Washington mated and began to oviposit within 7 days of removal from the field, suggesting that B. maculipennis overwinters in a temperature-controlled quiescence rather than in a true reproductive diapause. Eggs and nymphs of B. maculipennis were found on stems of C. arvensis well into November in Central Washington, suggesting that this psyllid also may overwinter in pre-adult stages, as indicated by literature accounts from the 1940s and 1950s. Lastly, we propose that successful colonization of the invasive and exotic weed C. arvensis by B. maculipennis has allowed the psyllid to expand its geographic range well beyond historical boundaries. This conclusion is based upon the scarcity of native Convolvulaceae within regions in which the psyllid is newly recorded, combined with the now extensive distribution of the invasive C. arvensis in North America.

New North American Records for the Old World Psyllid Heterotrioza chenopodii (Reuter) (Hemiptera: Psylloidea: Triozidae) with Biological Observations

Abstract. The Palearctic psyllid Heterotrioza chenopodii (Reuter) (Hemiptera: Psylloidea: Triozidae) belongs to a complex of psyllids having plants in the Amaranthaceae (including the former Chenopodiaceae) as hosts. Geographic records for this introduced species in North America date from 1988, and include a number of coastal regions in eastern Canada, the Northeastern U.S., inland Virginia, coastal British Columbia, California, and wetland habitats near Lincoln, Nebraska. We updated North American records for H. chenopodii to include inland Washington and Oregon, southwestern Idaho, northcentral California, western Colorado, and southern and central Alberta. Psyllids were collected from Atriplex micrantha (Amaranthaceae) and unidentified Atriplex species, and from yellow sticky cards that had been placed in potato fields to monitor arthropod pests of potatoes. Traits of the adult psyllid, fifth-instar nymph, and egg used in identifying specimens are summarized.We provide the first photographs of the egg, fifthinstar nymph, and terminalia of the adult male psyllid. Rearing trials showed that H. chenopodii developed on A. micrantha, A. hortensis, Chenopodium album, C. berlandieri, and garden beet, Beta vulgaris, but failed to develop on Amaranthus tricolor. Development was most rapid on the two Atriplex species. Heterotrioza chenopodii has been shown in Europe to exhibit photoperiod-controlled dimorphism in wing size, producing a long-winged form in spring and summer, and a short-winged form in autumn. We confirmed in rearing trials and by field collections that populations of H. chenopodii from central Washington State also exhibit this dimorphism. Short-winged forms began replacing long-winged forms in field populations between late August and early October.

The Potato Association of America Honorary Life Members, 2017

Robert (Rob) D. Davidson: I have known Rob since June 1983 and have found him a tremendous help, always willing to cooperate with others in the potato industry, the seed certification community, the seed certification section of the PAA and the PAA. His great interest in the PAA allowed him to often function as a liaison between seed certification officials and the PAA. Below is Rob’s career as a member of the potato community and family. Rob retired at the end of June 2016 and lives in Fort Collins, CO. Rob didn’t exactly plan for a career in potatoes. He graduated from Montana State University in Bozeman, Montana with a degree in Microbiology in 1975. While microbiology was a passion, Rob realized that a career in clinical pathology was not for him, since he didn’t want to be the bearer of bad news constantly diagnosing disease/illness. Instead, he took a job with the Montana Certified Seed Potato program as a lab supervisor. Somewhat unexpectedly, he found great pleasure in studying potatoes, opting to continue his education by earning another Bachelor of Science followed by a Master’s degree in Botany. While enrolled in school, Rob continued working full time in the lab, even overseeing up to 25 employees during the busy summer testing season. In 1982, Rob accepted the position of Assistant Manager of the Colorado Certified Seed Potato Program. Under the guidance of Ken Knutson, Rob learned managerial skills that would aid him when he became manager. A short time after moving to Colorado, Rob decided yet again to further his education by obtaining a PhD in Plant Pathology at Colorado State University, all the meanwhile, working his full time job. After becoming an official Doctor, his wife, Grace, asked if higher degrees existed. To her immense relief, Rob replied, no, signifying the official end to his graduate level education. Grace and their two children, Cristin and Nathan, breathed a collective sigh of relief as Rob had been taking classes or working towards a higher degree for 12 of their 14 years as a family. After Rob stepped down as the manager of the Colorado Certified Seed Potato Program, he accepted the position as manager of the San Luis Valley Research Center. He attended scientific meetings, performed research, managed the research center and even accepted an interim San Luis Valley Extension Director position for a couple of years. He published several scientific articles with co-workers in the American Journal of Potato Research. * Carrie Wohleb cwohleb@wsu.edu

The Potato Association of America 101 st Annual Meeting Fargo, North Dakota, USA July 23–27, 2017

President Report President Thornton reviewed his actions as PAA President. He noted that much of his time was dedicated to ensuring that the administrative office continued to function during Lori Wing’s extended leave of absence and retirement in May. He signed a contract with Association Management Resources (AMR) to provide administrative and financial services for the PAA from June 1 to Dec. 31, 2017. This action was recommended by the Office/ Association Services Committee and was approved by the EC in April. A complete report of his actions as President will be provided during the PAA Annual Business Meeting.