Phloem-feeding insects strive to offset the disadvantageous effects of stressors to sustain their offspring and survive. Adaptive responses to environmental stress are not well understood under complex influences of companion planting, natural enemies, and host gradient. In this study, under predation by lacewing Chrysoperla carnea Stephens (Neuroptera: Chrysopidae), we survey the responses of green peach aphid Myzus persicae Sulzer (Hemiptera: Aphididae), reared on different densities of cabbage Brassica oleracea L. (Brassicales: Brassicaceae) to its shallot companion Allium cepa (L.) var. aggregatum G. Don (Asparagales: Amaryllidaceae). Firstly, aphid aggregative abundance was strongly influenced by shallot perturbation, predator presence and changes in cabbage-host biomass, altering aphid phenotypic plasticity. Interestingly, the shallot and predation negative impacts can be of similar magnitudes. Secondly, changes in the cabbage-host availability and biomass, especially under predation, had a strong impact on aphid traits. Our study underscores the benefits of including shallots as crop-companions in augmenting pest control, but also suggests that the outcome of coupling companion planting with natural enemies is context-dependent and thus should be empirically applied. At the confluence of ecology and agronomy, this work provides insights on how manipulated functional biodiversity may function as an alternative strategy for pestilent herbivory management in model and green-house systems.

The soybean aphid (SBA; Aphis glycines Matsumura) and the soybean cyst nematode (SCN; Heterodera glycines Ichninohe) are major pests of the soybean (Glycine max (L.) Merr.). Independent studies on these pests have made substantial progress in understanding the genetic basis of limiting these pests in both model and non-model plant systems. Classical linkage mapping and genome-wide association studies (GWAS) have identified some major and minor QTLs in soybean. The studies on interactions of aphid and nematode effectors with host proteins allow us to identify molecular cues in various signaling components, including plant disease resistance and phytohormone genes. Here we review various resistance components of both SBA and SCN in terms of their effectors, their role in eliciting or attenuating host defense and update on findings on key quantitative trait loci (QTLs)/genes in soybean that could help in mitigating these widespread shifted virulent soybean aphid and SCN populations. We also provide an update on recent interaction studies of soybean-soybean aphid-SCN as well as interaction studies involving different aphids/nematodes and their host systems. PHYTOALEXIN DEFICIENT4 (PAD4) in soybean could possibly play a major role in providing resistance against both soybean aphid and SCN.

Virus diseases of strawberry present several complex problems. More than 25 viruses have been described in the genus Fragaria thus far. Here, we describe a novel rhabdovirus, tentatively named strawberry virus 1 (StrV-1), that infects F. ananassa and F. vesca plants. Genomic sequences of three distinct StrV-1 genotypes co-infecting a single F. ananassa host were obtained using combined Illumina and Ion Proton high-throughput sequencing. StrV-1 was transmitted to herbaceous plants via Aphis fabae and A. ruborum, further mechanically transmitted to Nicotiana occidentalis 37B and sub-transferred to N. benthamiana, N. benthamiana DCL2/4i, N. occidentalis 37B and Physalis floridana plants. Irregular chlorotic sectors on leaf blades and the multiplication of calyx leaves seem to be the diagnostic symptoms for StrV-1 on indexed F. vesca clones. StrV-1 was detected in asymptomatic grafted plants and in 49 out of 159 field strawberry samples via RT-PCR followed by Sanger sequencing. The bacilliform shape of the virions, which have a cytoplasm-limited distribution, their size, and phylogenetic relationships support the assignment of StrV-1 to a distinct species of the genus Cytorhabdovirus. Acyrthosiphon malvae, A. fabae and A. ruborum were shown to transmit StrV-1 under experimental conditions.