Mild Abiotic Stress Affects Development and Stimulates Hormesis of Hemp Aphid Phorodon cannabis

Abstract

The hemp aphid Phorodon cannabis Passerini is a well- known (Asia, Europe) or newly emerging (North America) insect. It is a monophagous insect pest causing considerable damage in field and glasshouse cultivations. The aim of this work was to study the effects of meteorological (temperature) and agronomical (herbicide) factors on the biology of the hemp aphid. In one experiment, hemp plants were kept at constant temperatures ranging from 20 to 30 °C, and aphid survival and fecundity were measured. In a related experiment conducted at 20 °C, plants were treated with field-appropriate rates of a selective graminicide containing quizalofop-P-tefuryl (40 gL−1, 4.38%, HRAC group 1), commonly used to control weeds in hemp, and aphid enzyme activity was measured in addition to population parameters. We found that hemp aphids could live, feed and reproduce within the whole studied range of temperatures, demonstrating its great evolutionary plasticity. However, the optimal temperature for development was 25 °C, at which the insect lived and reproduced for 25 and 15 days, respectively, with an average fecundity of 7.5 nymphs per reproduction day. The herbicide treatment increased the activity of superoxide dismutase (SOD), catalase (CAT), β-glucosidase, S-glutathione transferase (GST), oxidoreductive peroxidase (POD), and polyphenol oxidase (PPO) in the aphids, but only on certain days after treatment, which indicates a mild stress in aphid tissues, related to a higher reproduction and changed feeding behavior; aphids moved from the actively growing tips compared to untreated plants. The results of these experiments are discussed in terms of the impact on the future management of this pest.

Changes in Antioxidative, Oxidoreductive and Detoxification Enzymes during Development of Aphids and Temperature Increase

“…Temperature is one factor widely discussed as affecting longevity and it can determine the lifespan of many model organisms, for example, fungi Saccharomyces cerevisiae [ 55 ], Caenorhabditis elegans [ 56 ] or Drosophila melanogaster [ 32 ]. For aphids, it has also been noted that there is a negative correlation between temperature and longevity [ 57 , 58 , 59 ], but in some aphids, the opposite effect was observed in relation to the optimum temperature of the species [ 60 ]. Our research confirmed that metabolic rate is an important determinant of longevity, thus indicating that an increase in ambient temperature will increase enzyme activity and shorten aphid longevity.…”

“…Our results strongly correspond to the data obtained for the English grain aphid Sitobion avenae , which showed that the basal thermal tolerance of this species varied during development and was highest in the 3rd and 4th nymphs [ 61 ]. Changes in basal tolerance at the adult stage might result from a trade-off between heat tolerance and reproductive output, but may also result from behavioural thermoregulation abilities present in adult aphids [ 59 ]. Probably because the behavioural mechanisms of nymphs function poorly, we observed the need for high antioxidant activity of enzymes to effectively enable the protection of nymphs and allow them to continue development to maturity.…”

Evaluating the impact of light quality on plant–herbivore interactions using hemp as the model system

“…The cannabis aphid ( Phorodon cannabis Passerini) is a pest and monophagous herbivore of Cannabis spp. ( Cranshaw et al 2018 , Durak et al 2021 ). The aphid feeds by piercing the plant with its mouthparts and tapping directly into the phloem, ingesting the sugary sap produced through photosynthesis.…”

“…The aphid feeds by piercing the plant with its mouthparts and tapping directly into the phloem, ingesting the sugary sap produced through photosynthesis. Aphid herbivory can adversely affect the fitness and yield of Cannabis plants through direct damage and the transmission of plant viruses and is exacerbated by their capacity for rapid population growth ( McPartland et al 2000 , Durak et al 2021 , Pitt et al 2022 ). Their high reproductive potential, in addition to their ability to transmit viruses, contributes to their pest status.…”

Towards dsRNA‐integrated protection of medical Cannabis crops: considering human safety, recent‐ and developing RNAi methods, and research inroads

“…Perhaps the most important arthropod pests of indoor medical Cannabis cultivation include: cannabis aphid (Phorodon cannabis Passerini), rice root aphid (Rhopalosiphum abdominalis Sasaki), cotton/melon aphid (Aphis gossypii Glover), sweetpotato whitefly (Bemisia tabaci Gennadius), onion thrips (Thrips tabaci Lindeman), western flower thrips (Frankliniella occidentalis Pergande), twospotted spider mite (Tetranychus urticae Koch) and hemp russet mite (Aculops cannibicola Farkas). 18,23 Other arthropod pests of increasing consideration for outdoor medical Cannabis production include: Japanese beetle (Popillia japonica Newman), grasshoppers, brown marmorated stink bug (Halyomorpha halys Stål), Eurasian hemp moth (Grapholita delineana Walker) and corn earworm (Helicoverpa zea Boddie). 17,18,24 Pest management techniques are key in maintaining desirable crop yields in Cannabis production, but herein lies the complexity of producing healthy medicinal Cannabis plants in mass quantity.…”