Pest Management Science (2004) 60: 1099-1104.

Gábor Fekete, László A Polqár, Mária Báthori, Josep Coll and Béla Darvas

Per os efficacy of Ajuga extracts against sucking insects

We studied the efficacy of water-soluble extracts from four Ajuga spp. on the post-embryonic development of two exopterygota, sucking insect species. Crude methanolic extracts of all Ajuga plants – with the exception of A. genevensis – showed considerable per os efficacy on larvae of both tested insects even at 0.1% concentration. In the aphid tests the A. bracteosa > A. chamaepitys > A. reptans > A. genevensis order of efficacy was found. On D. cingulatus the order of efficacy was as follows: A. reptans > A. bracteosa > A. chamaepitys > A. genevensis. Among fractionated extracts the 100% methanolic SepPak fraction of A. chamaepitys was highly effective on Acyrthosiphon pisum (100% mortality at the concentration 0.1%) and less effective on Dysdercus cingulatus (about 60% mortality at the concentration 0.5%). The entire 60% methanolic SepPak fraction was effective on test insects but showed different efficacy according to test species and applied concentration. From the 60% methanolic SepPak fractions of all Ajuga species we have identified 20-hydroxyecdysone (20E), cyasterone (Cy) and ajugalactone (Ajl). The phytoecdysteroid profile was quite different between Ajuga species. Capitasterone (Cap) and 28-epi-sengosterone (5Cy28’) were found only in A. reptans, makisterone A (MaA) and 29-norcyasterone (29NCy) were only in A. chamaepitys, while 22-acetylcyasterone (Cy22A), 3-epi-cyasterone (Cy’) and 3-epi-22-acetylcyasterone (Cy’22A) were only in A. bracteosa. The total amount of phytoecdysteroids was 2053 mg litre-1 for A. bracteosa, 1892 mg litre-1 for A. reptans and 95 mg litre-1 for A. chamaepitys.