Zebra chip (ZC) disease of potato (Solanum tuberosum) is associated with infection by ‘Candidatus Liberibacter solanacearum’ (Lso). Two haplotypes of Lso—A and B—occur in the United States. Lso haplotype B is more virulent than haplotype A, causing greater disease incidence in tubers, more severe symptoms, and greater loss in tuber yield. This study assessed whether tubers from infected plants generate new infected plants the following year. The effects of both Lso haplotypes A and B on tuber resprout were examined on five potato cultivars. When compared with noninfected tubers, overall plant emergence rate from Lso A- or B-infected tubers was lower, plants emerged slower, and plants generated lower daughter tuber yields in weight and quantity. Plants generally emerged poorly from Lso B-infected tubers and produced lower daughter tuber yields than Lso A-infected tubers. Regardless of Lso treatment, all daughter tubers were asymptomatic, and only 0.3% tested positive for Lso in experiments conducted over 2 years. This suggests that plants generated from Lso A- and Lso B-infected seed potatoes with severe ZC symptoms are likely not a significant source of Lso in potato fields.

‘Candidatus Liberibacter solanacearum’ (Lso) causes disease symptoms and economic losses in potato, tomato, and other solanaceous crops in North America. Lso is transmitted to plants by the potato psyllid, Bactericera cockerelli, which occurs as distinct haplotypes named western, central, and northwestern that differ in the presence or absence of the bacterial endosymbiont, Wolbachia. Previous work showed that all three vector haplotypes can transmit Lso, but it was not clear whether acquisition and transmission rates of Lso were equal among the haplotypes. The goal of our study was to compare Lso infection rates among psyllids of the western, central, and northwestern haplotypes. Using data collected from several years of periodic testing of Lso infection of laboratory-reared potato psyllid colonies, we showed that psyllids of the western and central haplotypes are more likely to harbor Lso than are psyllids of the northwestern haplotype. We then used greenhouse assays to demonstrate that psyllids of the northwestern haplotype are less likely to acquire and transmit Lso than those of the western haplotype. Lso infection rates corresponded with Wolbachia infection among the three psyllid haplotypes. The Wolbachia-infected central and western haplotypes were more likely to harbor and transmit Lso than the Wolbachia-free northwestern haplotype. Results demonstrate that potato psyllids of the western and central haplotypes pose a greater risk for spread of Lso in crops and suggest a pattern between infection with Lso and Wolbachia in potato psyllid.

The recent introduction of fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae) into Pakistan has resulted in millions of dollars of losses for maize production. Due to the wide host range, high fecundity, and long-distance migrations favoring fall armyworm establishment, it has the potential to cause significant damage to several crops in Pakistan. In the maize cropping system, potato is another important crop that is cultivated on vast hectares. Okara is considered the hub of both maize and potato production in Pakistan. The existence of fall armyworm on maize could possibly threaten the potato crop. To ascertain the extent of possible damage from fall armyworm, we conducted a comprehensive survey of the potato growing area of the Okara District, Punjab, Pakistan. We collected twelve larvae from potato damaged plants from three different locations lat. 30.813979o, long. 73.533934o; lat. 30.725032o, long. 73.730319o and latitude 30.646966o, long. 73.786563o. Collected larvae were identified as fall armyworm. The plants from which the larvae were collected have a visible single hole at the base of the stem, which resulted in a sudden decline of feeding tiller. To our knowledge, this is the first report of fall armyworm occurrence and its damage on potato crop in Pakistan

The mechanism underlying the mediation of the behavior and fitness of non-vector herbivores by fungal pathogen-infected host plants is still unclear. In this study, we experimentally assessed the effects of tomato (Lycopersicon esculentum L.) plant infection status on non-vector herbivores using tomato powdery mildew disease fungus (Oidium lycopersici) and the greenhouse whitefly Trialeurodes vaporariorum as a model multitrophic plant-pathogen, non-vector herbivore interaction. In behavioral bioassays, powdery mildew-infected plants (PM) and plants damaged by combined attack of powdery mildew and whiteflies (PMWF) attracted significantly more whiteflies (32.6% and 58.1% for PM and PMWF, respectively) than control (Con) plants (16.5%) or plants damaged only by whiteflies (WF) (24.2%). Whiteflies feeding on PM or PMWF plants secreted almost twice as much honeydew as on the Con or WF plants. This indicated that whiteflies fed more on diseased plants than healthy plants. However, the preferences and increased feeding did not increase the fitness and immature growth of T. vaporariorum, but significantly prolonged their immature developmental durations, compared with those of whiteflies that developed on Con plants or WF plants. The results showed that powdery mildew infestation attracted more whiteflies but reduced their development and fitness.