Waterlogging increases the infestation level of the pest psyllidCreiis lituratusonEucalyptus dunnii

Abstract

The lerp-forming psyllid, Creiis lituratus Froggatt, is the most damaging pest of Euca~Jptus dunnii Maiden plantations growing in north-eastern New South Wales. During the past I 0 years there have been numerous reports that stands of E. dunnii planted on low-lying areas that were prone to waterlogging were also prone to infestation by C. lituratus. The objective of this shadehouse study was to determine whether C. /ituratus prefers young E. dunnii exposed to intermittent waterlogging compared with other treatments (drought, normal watering and a control using normal watering plus an insecticide). Also we assessed whether the nutritional status of E. dunnii foliage, in particular amino acid content, differed between watering treatments. Field-collected C. lituratus adults were released into the shadehouse three months after establishing the watering treatments to individually-potted E. dunnii arranged in a 14 x 6 randomised design. Three months after release of the psyllids, we counted significantly more eggs and nymphs present on the plants subjected to intermittent waterlogging compared with the other treatments. Applying general linear modelling (GLM) and Akaike's information criterion (AIC) we found that the best model included both watering treatment and plant structure (through height and diameter), with psyllid infestation (eggs+ nymphs) significantly higher on the waterlogged plants and significantly lower in the drought treatment compared with the normal watering treatment. The application of the generalised estimating equations technique to foliar content of individual amino acids and nutrients did not reveal a clear association with watering treatment or psyllid infestation. Most of the significant differences in amino acid content between treatments were between plants watered normally but with or without the systemic insecticide imidacloprid applied as a soil drench. No eggs or nymphal stages were recorded on the plants treated with imidacloprid. This trial demonstrated that the psyllid C. lituratus has a preference tor young E. dunnii subjected to periodic waterlogging. Plantation growers can improve their site-species match for E. dunnii by avoiding sites prone to waterlogging.

Senescence‐feeders: a new trophic sub‐guild of insect herbivores

“…Populations are most active over autumn‐winter months and their nymphs cause the tissues around their feeding site to discolour and die. Other species of Creiis cause the same damage and occasionally increase to outbreak proportions on a variety of eucalypts (Carnegie and Angel ; Stone et al ).…”

Drought and flooding have distinct effects on herbivore‐induced responses and resistance inSolanum dulcamara

“…In the field, different stresses may co-occur, causing interactions between plant responses that can compromise adaptation to individual stresses (Atkinson & Urwin 2012;Suzuki et al 2014). Ecological studies showed that abiotic stresses such as drought and flooding affect the performance and behaviour of insect pests (Huberty & Denno 2004;Stone et al 2010;Khan et al 2011;Chakraborty et al 2014;Rivas-Ubach et al 2014). Knowledge of molecular mechanisms underlying these effects, however, is very limited.…”

Shoot Feeding as a Nutrient Acquisition Strategy in Free-Living Psylloids

“…Of the three studies known to the author, one did not quantify concentrations of individual amino acids [28] and another does not relate the concentrations of individual amino acids to psyllid survival or development [29]. The third study found that concentrations of isoleucine decreased when heather was grown under increased UVB and it was suggested that this might explain the decline in abundance of the psyllid Strophingia ericae [30].…”