Toona

About: Toona is a research topic. Over the lifetime, 105 publications have been published within this topic receiving 1251 citations.

Leaves from grafted Meliaceae species affect survival and performance of Hypsipyla grandella (Zeller) (Lepidoptera: Pyralidae) larvae

Abstract: In order to determine their effects on growth and mortality of instar II Hypsipyla grandella (Zeller), larvae were fed with leaf disks taken from shoots of susceptible species (Cedrela odorata L. and Swieteniamacrophylla King) scions grafted onto resistant ones (Khaya senegalensis Desr. A. Juss and Toona ciliata M. Roem.), from their reciprocal grafts, and from both intact and autografted plants. In addition, crude leaf extracts from the susceptible and resistant plants, as well as from C. odorata grafted onto T. ciliata plants, were tested on C. odorata leaf disks. Mortality was evaluated 2, 10, and 25 days after starting the bioassay. Leaf area consumed and weight gain per larva were assessed 2 days after starting bioassay. Time to reach pupation, pupal weight and length 1 day after pupation, and time to adult stage and appearance of wings were determined at the end of the bioassay. Plant species significantly affected mortality (P ≤ 0.04) throughout the test. Eighty to 100% of larvae fed leaf disks from intact T. ciliata and its autograft, or C. odorata onto T. ciliata and its reciprocal graft died in the first 2 days of evaluation. All other factors measured, except pupal weight and length, were also affected (P ≤ 0.01) by the leaf disks. Intact resistant plants and reciprocal grafted plants reduced leaf consumption and caused larval weight loss. Larvae fed on K. senegalensis grafted onto S. macrophylla extended by 8 days the time to pupa and to adult stages and induced abnormal wing formation compared to larvae fed intact leaves of C. odorata. Crude extracts from resistant plants equally affected larval survival and performance compared to crude extract from C. odorata grafted onto T. ciliata plants, and these extracts were more detrimental to larvae than those from susceptible species. This study demonstrated that grafting borer-susceptible species on resistant rootstocks can affect the survival and performance of instar II H. grandella larvae.

Hypsipyla Shoot Borers in Meliaceae: Proceedings of an International Workshop held at Kandy, Sri Lanka 20–23 August 1996

Abstract: Damage from shoot borers of the genus Hypsipyla Ragonot present the greatest deterrent to the establishment and cultivation of the high value timber species belonging to the family Meliaceae, including species of Swietenia, Khaya, Toona and Cedrela. The most serious damage to the tree results from the tunnelling of the lava in the developing shoots. This boring leads to the death of the terminal shoot and subsequent production of laterals, eventually resulting in a stunted, continuously branched and crooked tree of greatly diminished value for timber production. Growth rate is reduced and death can result from heavy and repeated attacks. This publication contains the papers presented at an International Workshop held at Kandy, Sri Lanka 20-23 August 1996. The review describes the biology and ecology of the main Hypsipyla species and highlights areas warranting further research.