Bioactivity of some Apiaceae essential oils and their constituents againstSitophilus zeamais(Coleoptera: Curculionidae)

Sitophilus zeamaisis a key pest of stored grains. Its control is made, usually, using synthetic insecticides, despite their negative impacts. Botanical insecticides with fumigant/repellent properties may offer an alternative solution. This work describes the effects ofAnethum graveolens,Petroselinum crispum,Foeniculum vulgareandCuminum cyminumessential oils (EOs) and (S)-carvone, cuminaldehyde, estragole and (+)-fenchone towards adults ofS. zeamais. Acute toxicity was assessed by fumigation and topical application. Repellence was evaluated by an area preference bioassay and two-choice test, using maize grains. LC(50)determined by fumigation ranged from 51.8 to 535.8 mg L(-1)air, with (S)-carvone being the most active. LD(50)values for topical applications varied from 23 to 128 mu g per adult for (S)-carvone > cuminaldehyde >A. graveolens>C. cyminum>P. crispum. All EOs/standard compounds reduced significantly the percentage of insects attracted to maize grains (65-80%) in the two-choice repellence test, whereas in the area preference bioassay RD(50)varied from 1.4 to 45.2 mu g cm(-2), with cuminaldehyde, (S)-carvone and estragole being strongly repellents.Petroselinum crispumEO and cuminaldehyde affected the nutritional parameters relative growth rate, efficiency conversion index of ingested food and antifeeding effect, displaying antinutritional effects towardS. zeamais.In addition,P. crispumandC. cyminumEOs, as well as cuminaldehyde, showed the highest acetylcholinesterase inhibitory activityin vitro(IC50= 185, 235 and 214.5 mu g mL(-1), respectively). EOs/standard compounds exhibited acute toxicity, and some treatments showed antinutritional effects towardsS. zeamais.Therefore, the tested plant products might be good candidates to be considered to prevent damages caused by this pest.