Non-odorous characteristics of lychee (Litchi chinensis) and carambola (Averrhoa carambola) pertaining to fruitpiercing moth susceptibility

Abstract

Lychee (Litchi chinensis Sonn.) and carambola (Averrhoa carambola L.) fruit, either attacked by fruitpiercing moths or undamaged, were compared on a number of occasions for weight, moisture percentage, softness, colour, ¦Brix, and pH, to profile fruit susceptibility in North Queensland. Height at which fruit were damaged on a tree and the tree's position in an orchard were also considered. On average 88.8% of moths inflicting damage to all fruit were Othreis fullonia (Clerck). In both crops, fruit in outer rows were more prone to attack than elsewhere in an orchard, indicating that orchard layout, trap crops, and attractive baits could all be considered to counteract these pests. No other characteristic differed significantly (P>0.05) between damaged and adjacent undamaged lychees. In damaged lychees, ¦Brix ranged from 11.0 to 22.8 and pH varied from 3.3 to 4.8. Highly significant (P<0.001) differences in fruit weight, colour, ¦Brix, and pH were recorded between damaged and undamaged carambolas; riper fruit were attacked on any individual occasion. Total soluble solids ranged from 5.2 to 11.8 ¦Brix in damaged carambolas and pH varied from 2.5 to 4.4. Some comparisons between cultivars were undertaken in each crop.