Inhibitory effects of an extract from non-host plants on physiological characteristics of two major cabbage pests

Abstract

The diamondback moth (Plutella xylostella) and small white cabbage butterfly (Pieris rapae) are the two main serious pests of cruciferous crops (Brassicaceae) that have developed resistance to chemical control methods. In order to avoid such resistance and also the adverse effects of chemical pesticides on the environment, alternative methods have usually been suggested, including the use of plant enzyme inhibitors. Here, the inhibitory effects of proteinaceous inhibitors extracted from wheat, canola, sesame, bean and triticale were evaluated against the digestive α-amylases, larval growth, development and nutritional indecs of the diamondback moth and small white cabbage butterfly. Our results indicated that triticale and wheat extracts inhibited α-amylolytic activity in an alkaline pH, which is in accordance with the moth and butterfly gut α-amylase optimum pH. Dose-dependent inhibition of two crucifer pests by triticale and wheat was observed using spectrophotometry and gel electrophoresis. Implementation of specificity studies showed that wheat and triticale-proteinaceous extract were inactive against Chinese and purple cabbage amylase. Triticale and wheat were resistant against insects' gut proteases. Results of the feeding bioassay indicated that triticale-proteinaceous extract could cause a significant reduction in survival and larval body mass. The results of the nutritional indecs also showed larvae of both species that fed on a Triticale proteinaceous inhibitor-treated diet had the lowest values for the efficiency of conversion of ingested food and relative growth rate. Our observations suggested that triticale shows promise for use in the management of crucifer pests.

Polyphenol-Rich Purple Corn Pericarp Extract Adversely Impacts Herbivore Growth and Development

“…Similar to the results reported by Datta et al (2019) in tobacco cutworm (Spodoptera litura) caterpillars with Greater galangal (Alpinia galanga) extracts, we found that M. sexta larvae fed on purple corn pericarp extract-containing diet had lower mass and mass gain in early larval stages ( Figure S4A,B and Figure 5A,B) [68]. The low mass and mass gain might be due to either the negative impact of pericarp extract ingested by them through diet or its antifeedant properties [2,[70][71][72][73][74]. To confirm this, we did a no choice (on/off) and a choice assay using Ethovision behavior tracking system.…”

Induction of Resistance Against Plutella xylostella (L.) (Lep.: Plutellidae) by Jasmonic Acid and Mealy Cabbage Aphid Feeding in Brassica napus L.

“…In our study, artificial induction of defense in oilseed rape plants reduced the survivorship of immature stages of P. xylostella . Probably, the reduction in the survival rate of P. xylostella was because of the increase of inhibitor level in treated plants that affect the feeding, growth, and survival of the immature ( Dastranj et al, 2017 ). Also, inducers are responsible for producing certain secondary metabolites which decrease the survival of herbivores ( Thaler et al, 2001 ).…”

“…Besides glucosinolate, other secondary metabolites and digestive enzyme inhibitors might have changed and influenced the r of P. xylostella ; as its correlation is shown in Table 4 . Dastranj et al (2017) reported that plant inhibitors reduced survival and delayed growth and development of the P. xylostella larvae.…”

“…Nutritional indices were determined as described by Waldbauer (1968) , Manuwoto and Scriber (1982) , and Farrar et al (1989) with some modifications by Dastranj et al (2017) . Initially, neonates were reared on the treated and control plants until the unset of fourth instar.…”

A new 24-membered macrolide shows insecticidal activity against Pieris rapae potentially through induction of programmed cell death

“…Pieris rapae, one of the major pests of cabbage, has developed resistance to chemical control, so it is one of the most serious and difficult pests to control (Dastranj et al, 2017). Natural pesticides have a number of advantages over synthetic pesticides; they are biodegradable and tend to cause minimal harm to humans, livestock, and wildlife (Benelli, 2016).…”