Phillips Wendy S, Kitner Megan, Zasada Inga A
United States Department of Agriculture-Agricultural Research Service Horticultural Crops Research Laboratory, Corvallis, OR 97330.
Plant Dis. 2017 Jul;101(7):1182-1187. doi: 10.1094/PDIS-10-16-1439-RE. Epub 2017 Apr 28.
Globodera ellingtonae is a recently described nematode parasite of potato, which is closely related to the economically significant potato cyst nematodes G. rostochiensis and G. pallida. Because of the close relationship of G. ellingtonae to the potato cyst nematodes, a greater understanding of its biology is critical. Two experiments were conducted in Oregon to explore the developmental biology of G. ellingtonae in field-grown potato. The first experiment was conducted in 2013 and 2014 to determine the developmental timing of G. ellingtonae life stages and reproduction by inoculating potato with soil containing cysts followed by weekly collection of soil and root samples. Life stages; second-stage juveniles (J2) in soil and roots, third-stage juveniles (J3) and fourth-stage (J4) females and males in roots, males and females or cysts in soil, and egg number and developmental state were quantified. Normalizing across years using accumulated developmental degree days above 6°C (DD6), J2 of G. ellingtonae were found in soil from 41 to 588 DD6; two peaks of J2 invasion of roots were observed. The first adult females were observed at 387 and 449 DD6 in 2013 and 2014, respectively. The next generation of eggs was first observed from 675 to 854 DD6 and 50% egg development (containing a vermiform juvenile) occurred at approximately 920 DD6. A second J2 hatch was observed in both years at 927 to 1,073 DD6. The developmental dynamics of G. ellingtonae observed here are similar to those reported for G. rostochiensis and G. pallida from several geographical locations. In the second experiment, the effect of potato and bare soil on G. ellingtonae egg hatch was evaluated; in 2014 and 2015, packages containing cysts in soil were buried under potato or in bare soil at the time of planting and eggs per cyst determined weekly. Across years, a significant reduction in eggs per cysts under potato (>50%) was observed 35 days after planting (DAP) and, at 63 DAP, eggs per cyst were reduced by 76 to 96% compared with initial egg per cyst densities. In bare soil, the maximum reduction in densities of eggs per cyst was 55 to 73%. This annual reduction in egg numbers of G. ellingtonae in bare soil is similar to that reported for G. pallida and G. rostochiensis.
埃氏球孢囊线虫是一种最近被描述的马铃薯线虫寄生虫，它与具有经济重要性的马铃薯孢囊线虫罗斯托克球孢囊线虫和苍白球孢囊线虫密切相关。由于埃氏球孢囊线虫与马铃薯孢囊线虫关系密切，更深入了解其生物学特性至关重要。在俄勒冈州进行了两项实验，以探究田间种植马铃薯中埃氏球孢囊线虫的发育生物学。第一个实验在2013年和2014年进行，通过用含有孢囊的土壤接种马铃薯，随后每周采集土壤和根系样本，来确定埃氏球孢囊线虫各生活阶段的发育时间和繁殖情况。对生活阶段进行了量化：土壤和根系中的第二龄幼虫（J2）、根系中的第三龄幼虫（J3）和第四龄（J4）雌虫和雄虫、土壤中的雄虫和雌虫或孢囊，以及卵的数量和发育状态。使用6°C以上的累积发育度日（DD6）对年份进行标准化后发现，在41至588 DD6的土壤中发现了埃氏球孢囊线虫的J2；观察到J2侵入根系有两个高峰。在2013年和2014年，分别在387和449 DD6观察到第一批成年雌虫。下一代卵最早在675至854 DD6被观察到，约920 DD6时发生50%的卵发育（含有一条蠕虫状幼虫）。在这两年中，927至1073 DD6时均观察到第二次J2孵化。这里观察到的埃氏球孢囊线虫的发育动态与几个地理位置报道的罗斯托克球孢囊线虫和苍白球孢囊线虫的发育动态相似。在第二个实验中，评估了马铃薯和裸土对埃氏球孢囊线虫卵孵化的影响；在2014年和2015年，在种植时将装有土壤中孢囊的包裹埋在马铃薯下或裸土中，并每周测定每个孢囊的卵数。多年来，种植后35天（DAP）观察到马铃薯下每个孢囊的卵显著减少（>50%），与初始每个孢囊的卵密度相比，在63 DAP时，每个孢囊的卵减少了76%至96%。在裸土中，每个孢囊卵密度的最大减少量为55%至73%。裸土中埃氏球孢囊线虫卵数量的这种年度减少与苍白球孢囊线虫和罗斯托克球孢囊线虫报道的情况相似。
