Lethal and Sublethal Effects of Essential Oils fromEucalyptus camaldulensisandHeracleum persicumAgainst the Adults of Callosobruchus Maculatus

Abstract

The cowpea weevil, Callosobruchus maculatus F. (Coleoptera: Bruchidae), is an important pest of stored cowpea, Vigna ungiculata (L.) Walpers (Fabales: Fabaceae), with ample distribution in tropical and subtropical regions. Many plant essential oils have a broad-spectrum activity against pest insects, and these oils traditionally have been used in the protection of stored products. In this study, the lethal and sublethal effects of essential oils from Eucalyptus camaldulensis Dehnh. (Myrtales: Myrtaceae) and Heracleum persicum Desf. (Apiales: Apiaceae) were evaluated on the adults of C. maculatus at 26 ± 1° C, 70 ± 5% RH, and a photoperiod of 16:8 L:D. The LC50 values of E. camaldulensis and H. persicum were 56.7 and 219.4 µL/L air after 12 hr and 26.1 and 136.4 µL/L air after 24 hr of exposure, respectively. The LT50 values of E. camaldulensis and H.persicum were 6.3 and 10.9 hr, respectively. The results showed that low lethal concentration (LC20) of essential oils negatively affected the longevity, fecundity, and fertility of female adults. The sex ratio of C. maculatus offspring was not significantly affected by essential oils. Therefore, these essential oils can be suggested for controlling C. maculatus in storage systems. The introduction of essential oils into storage systems could potentially decrease seed losses.

Chemical composition and bio-pesticidal values of essential oil isolated from the seed of Heracleum persicum Desf. ex Fischer (Apiaceae)

“…LC 50 value in this study was 337.38 μL L -1 that was much more than our LC 50 values. In the study of Izakmehri et al (2013), the lethal and sublethal effects of essential oils from H. persicum were evaluated on C. maculatus adults. The LC 50 value of H. persicum was 219.4 μL L -1 air after 12 h and 136.4 μL L -1 air after 24 h of exposure, respectively.…”

Essential Oils in Stored Product Insect Pest Control

“…To determine the sublethal effects of the Eucalyptus camaldulensis (Myrtaceae) and Heracleum persicum (Apiaceae) EOs on C. maculatus females, a sublethal dose (i.e., LC 20 ) was tested for 24h as fumigation. After the treatment, the number of total and daily eggs laid for C. maculatus females was significantly reduced for both EOs, even if it was slightly higher (39.58% reduction) for H. persicum than for E. camaldulensis (27.58%) [126]. Fumigation with low doses of EOs could also alter fecundity in Lepidoptera.…”

Leptospermum scoparium essential oil is a promising source of mosquito larvicide and its toxicity is enhanced by a biobased emulsifier

“…However, essential oils are also known to cause a variety of sublethal effects that are detrimental to insect survival and reproduction. These effects include repellency, irritability, altered respiratory activity, changes in swimming pattern, and reduced adult emergence, longevity, fertility, fecundity and natality [49][50][51][52]. Future studies evaluating both the lethal and sublethal effects of L. scoparium essential oil, its fractions and emulsions could reveal the full spectrum of their biological effects against mosquitoes.…”