- Tertia Grové, Marinda S de Beer, Sonja Dreyer and W P Steyn
- Institute for Tropical and Subtropical Crops, Private Bag x11208, Nelspruit 1200
- 1999
Fruit flies were monitored at two different localities in litchi orchards to determine which species occurs the most abundantly. Monitoring was conducted in orchards near Nelspruit and Malelane. Sensus traps with 8-caryophyllene as well as a milk bottle trap with a protein hydrolysate were used. The dominance of the Natal fruit fly, Ceratitis rosa Karsch, in the Sensus as well as in the milk bottle traps, suggested that this species could be responsible for most damage caused by fruit flies in litchi orchards. C rosa was the most abundant species in both areas. The Marula fruit fly, Ceratitis cosyra (Walker), does not seem to be of any importance in litchi production.
Summary:
Monitoring of fruit flies was conducted in litchi orchards near Nelspruit and Malelane to identify the most abundant species.
Two types of traps were used: Sensus traps baited with 8-caryophyllene and milk bottle traps baited with protein hydrolysate (Hymlure mixed with pesticide).
The Natal fruit fly, Ceratitis rosa Karsch, was dominant in both trap types and locations, indicating it is likely responsible for most fruit fly damage in litchi orchards.
The Mediterranean fruit fly, Ceratitis capitata, was present but in much lower numbers and appears less important in litchi production.
The Marula fruit fly, Ceratitis cosyra, was found to be insignificant in litchi orchards and more associated with Marula trees.
Fruit flies sting litchi fruit during ripening; initial sting marks are invisible but lead to fermentation and skin cracking.
Larvae seldom develop inside litchi fruit because fermentation causes eggs and maggots to be forced out.
Fruit fly control is preventive, based on weekly baiting, typically starting between mid-September and October depending on the region.
Traps are essential to monitor populations for effective timing of control measures.
Monitoring showed fruit fly numbers start increasing in November and December.
More females of C. rosa were caught in milk bottle traps, while more males were caught in Sensus traps.
Aerial bait applications on Riverside Farm kept infestation levels low.
Morphological descriptions of fruit fly species were included to help identification.