caa a22 4500 38810547X CHVBK 20180307125336.0 cr unu---uuuuu 161130e199903 xx s 000 0 eng 10.1017/S1742758400016635 doi S1742758400016635 pii (NATIONALLICENCE)cambridge-10.1017/S1742758400016635 Seasonal changes of secondary compounds in the phloem sap of cassava in relation to fertilisation and to infestation by the cassava Mealybug [Elektronische Daten] The aim of the present study was to determine, by a field experiment, whether the seasonal variations in the levels of cyanide and rutin in the phloem, secondary compounds potentially implicated in cassava resistance to the cassava mealybug (Phenaccocus manihoti), could be influenced by different kinds of soil fertilisation (manure, NPK, KC1, lime, mulch). It was found that mean cyanide and rutin contents varied significantly with season, soil treatments and infestation. For each soil treatment, the highest contents of these compounds on uninfested plants was registered in the main dry season (Jul-Aug) for cyanide and at the end of the dry season (Jul-Aug) and beginning of the rainy season (Oct-Nov) for rutin. The infestation factor induced an increase in cyanide and rutin contents for 43 combinations of period and soil treatment among 48 in total. For cyanide content (phagostimulant function in mealybug), this increase appeared significant at the end of the rainy season (Apr-May) and in the main dry season (Jul-Aug) for control and KC1 fertilisation. For rutin content (an unfavourable substance for the insect) significant increase was induced by infestation in each period for manure and mulch and especially in the main dry season (Jul-Aug) and at the beginning of the rainy season (Oct-Nov) for other soil treatments. Concerning the seasonal variations in the level of rutin, these results showed that mulch and manure are the best fertilisers to increase cassava resistance against mealybugs. Copyright © ICIPE 1999 Phenacoccus manihoti nationallicence Pseudococcidae nationallicence Manihot esculenta nationallicence cassava nationallicence antixenosis nationallicence antibiosis nationallicence phloem sap nationallicence nitrogen fertilisation nationallicence cyanogenic glucosides nationallicence plant phenolics nationallicence rutin nationallicence Phenacoccus manihoti nationallicence Pseudococcidae nationallicence Maniliot esculenta nationallicence manioc nationallicence antixénose nationallicence antibiose nationallicence sève phloémienne sap nationallicence fertilisation azotée nationallicence glycosides cyanogénés nationallicence phénols nationallicence rutine nationallicence Tertuliano M. ORSTOM, Laboratory of Entomology, B.P. 181, Brazzaville, Congo Calatayud P. A. ORSTOM, Laboratory of Entomology, B.P. 181, Brazzaville, Congo Le Rü B. P. ORSTOM, Laboratory of Entomology, B.P. 181, Brazzaville, Congo International Journal of Tropical Insect Science Cambridge University Press 19/1(1999-03), 91-98 1742-7584 19:1<91 1999 19 JTI https://doi.org/10.1017/S1742758400016635 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1017/S1742758400016635 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Tertuliano M. ORSTOM, Laboratory of Entomology, B.P. 181, Brazzaville, Congo NATIONALLICENCE 700 1- Calatayud P. A. ORSTOM, Laboratory of Entomology, B.P. 181, Brazzaville, Congo NATIONALLICENCE 700 1- Le Rü B. P. ORSTOM, Laboratory of Entomology, B.P. 181, Brazzaville, Congo NATIONALLICENCE 773 0- International Journal of Tropical Insect Science Cambridge University Press 19/1(1999-03), 91-98 1742-7584 19:1<91 1999 19 JTI CC0 http://creativecommons.org/publicdomain/zero/1.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-cambridge