Działanie przeciwszkodnikowe wyciągów z wybranych gatunków roślin i ich izolatów przeciwko strąkowcowi czteroplamemu Callosobruchus maculatus (F.) (Coleoptera: Chrysomelidae: Bruchinae)

Different extracts from seven plant species were assayed against the cowpea beetle (Callosobruchus maculatus) in the laboratory. The plants were extracted sequentially with petroleum ether, chloroform and ethyl alcohol. The petroleum ether extract of each was fractionated into sap and unsap, then identified by GC chromatography. Also compounds isolated from chloroform and alcohol extracts of Citrullus colocynthis and petroleum ether extract of Nicandra physaloides were tested for their toxicity against the adult beetle. The sensitivity of the adults to various crude extracts revealed great variation in effectiveness. Petroleum ether and chloroform extracts of Nicandra physaloides proved to be the most toxic in comparison to other extracts tested, while petroleum ether extracts of Curcuma longa proved to be the least effective. All the fatty acid fractions of the seven plant species were toxic to the adult beetles at the tested concentrations. N. physaloides, Schinus terebinthifolius and Dodonaea viscosa resulted in 100% mortality of adults at the highest concentration tested (1.0%). Using 1.0% unsap fraction of Dodonaea viscosa resulted in 100% mortality between the adults. The least percentage mortality between the adult beetles recorded (22%) was for unsap fraction of T. orientalis at concentration of 0.0625% but increased to 80.0% mortality at concentration of 1.0%. The compounds isolated from chloroform and alcohol extracts of C. colocynthis and petroleum ether extract of N. physaloides proved to be highly efficient against C. maculatus adults.W niniejszych badaniach przetestowano wpływ wyciągów z siedmiu gatunków roślin na śmiertelność strąkowca czteroplamego. Materiał roślinny ekstrahowano stosując kolejno: eter naftowy, chloroform oraz alkohol etylowy. Wyciągi eterowe były frakcjonowane do fazy zmydlającej i niezmydlającej się, a następnie identyfikowano je za pomocą chromatografii gazowej. Testowano również toksyczność związków wyizolowanych z chloroformowego i alkoholowego wyciągu z Citrullus colocynthis oraz eterowego wyciągu z Nicandra physaloides. Wrażliwość dorosłych osobników strąkowca na działanie poszczególnych surowych wyciągów roślinnych wykazywała duże zróżnicowanie. Wyciąg eterowy i chloroformowy z Nicandra physaloides był najbardziej toksyczny w porównaniu z innymi badanymi ekstraktami, natomiast wyciąg eterowy z Curcuma longa miał najniższą skuteczność. Wszystkie frakcje kwasów tłuszczowych siedmiu badanych gatunków roślin były toksyczne dla dorosłych chrząszczy w analizowanych stężeniach. Zastosowanie wyciągów z N. physaloides, Schinus terebinthifolius i Dodonaea viscosa skutkowało 100% śmiertelnością dorosłych osobników w najwyższym testowanym stężeniu (1,0%). 1,0% frakcja niezmydlająca się uzyskana z Dodonaea viscosa powodowała 100% śmiertelność dorosłych osobników. Najniższą procentową śmiertelność dorosłych chrząszczy (22%) zanotowano przy zastosowaniu frakcji niezmydlającej się z Thuja orientalis w stężeniu 0,0625%, ale wzrosła ona do 80,0% przy stężeniu 1,0%. Wykazano, że składniki wyizolowane z chloroformowego i alkoholowego wyciągu z C. colocynthis i eterowego ekstraktu z N. physaloides są bardzo skuteczne przeciw dorosłym osobnikom C. maculatus

Extratos aquosos de plantas e o comportamento do ácaro verde da mandioca Aqueous plant extracts and the behavior of the cassava green mite

Extratos de plantas são uma alternativa promissora no controle de ácaros fitófagos. Neste trabalho estudou-se a bioatividade de extratos aquosos de nim, Azadirachta indica A. Juss. e cravo-da-índia, Syzigium aromaticum L., na biologia do ácaro verde da mandioca, Mononychellus tanajoa (Bondar). Larvas recém-eclodidas foram individualizadas em discos de folhas de mandioca previamente imersos nos extratos e em água destilada, e mantidas nestas condições até atingir a fase adulta. Após a emergência, as fêmeas foram individualizadas em discos não tratados e acasaladas com machos coletados da criação estoque. As avaliações foram efetuadas a cada 12 h. As duas maiores concentrações de nim (1,0 e 0,75g do pó de sementes de nim 100 mL-1 de água) deram os melhores resultados, causando 72,5 e 37,5% de mortalidade larval, respectivamente, e até 16% para os estágios seguintes. A mortalidade em todo estágio imaturo foi de 84,6 e 55%, respectivamente. A duração da fase deutocrisálida e teliocrisálida foi levemente afetada, porém significativamente maior para o nim a 1%. Os extratos não afetaram a fecundidade, a qual variou de 6,5 a 8,6 ovos/fêmea/dia. Embora os extratos usados não tenham afetado o período de incubação, nim a 1% reduziu significativamente a viabilidade dos ovos.<br>The use of plant extracts is a promising alternative for the control of phytophagous mites. This study was carried out to test the bio-activity of neem, Azadirachta indica A. Juss. and clove, Syzigium aromaticum L., aqueous extracts on the behaviour of the cassava green mite, Mononychellus tanajoa (Bondar). Recently hatched larvae were individualized onto cassava leaf discs previously immersed in different concentrations of the extract and in distilled water, and maintained at these conditions until reaching maturity. The females were individualized onto untreated leaf discs right after emergency and mated with males from the rearing stock. The evaluations were taken each 12 h. The two highest neem concentrations (1.0 and 0.75g of ground neem seeds 100 mL-1 water) gave the best results, causing 72.5 and 37.5% of larval mortality, respectively. Mortality of other stages was up 16%. The mortality of the combined immature stages was 84.6 and 55%, at neem concentrations of 1.0 and 0.75%, respectively. The duration of the deutochrysalis and teleiochrysalis stages was slightly but significantly longer for neem at 1.0% probability. The plant extracts did not affect female fecundity, which ranged from 6.5 to 8.6 eggs/female/day. Although the extracts used did not affect the incubation period, neem extract significantly reduced egg viability at 1% probability