- Schalk Schoeman, Willem Steyn, Tertia Grove, Marinda de Beer and Rachel Mohlala
- Agricultural Research Council-Institute for Tropical and Subtropical Crops, Private Bag Xl 1208 Nelspruit 1200, South Africa
- 2007
The objectives of this study were to research the biology of the litchi moth Cryptophlebia peltastica (Meyrick) (Lepidoptera: Tortricidae) with the aim of improving timing of chemical control, evaluate potentially effective pesticides and to develop an effective rearing technique for the insect in captivity. Chemicals were applied when the mean mass of a sub sample of aborted fruit reached approximately 2 g. Although slight differences were observed between the treatments, all three compounds were able to contain the litchi moth effectively. Litchi moth females preferred to oviposit on larger fruit which appeared to be comparable to the population dynamics of tortricid moths on macadamias. The relative seasonal abundance of damage to the fruit were also similar to damage patterns of tortricid moths on macadamias, although further research is required to clarify this observation conclusively. Significant controversy
currently exists regarding damage symptoms of litchi moth versus fruit flies. To complicate matters further it was also observed that the coconut bug, Pseudotheraptus wayi (Hemiptera: Coreidae), fed on litchis towards the end of the fruit maturation phase. Additionally, an unidentified coreid bug was also observed on two localities in the Nelspruit region. Damage symptoms and habits of the pests species concerned are briefly discussed in an attempt to elucidate the current situation, as wrong interpretations could have significant financial implications for the producer.
Summary:
The study focuses on the biology and control of the litchi moth (Cryptophlebia peltastica) to improve chemical control timing, evaluate pesticides, and develop rearing techniques.
Three pesticides were tested and all effectively controlled the litchi moth when applied as fruit mass reached approximately 2 grams.
Female litchi moths prefer to lay eggs on larger fruit, similar to tortricid moth behavior on macadamias.
Seasonal damage patterns of the litchi moth resemble tortricid moth damage on macadamias, though further research is needed.
There is current controversy distinguishing damage caused by the litchi moth versus fruit flies, further complicated by coconut bug and other coreid bug damage on litchis.
Effective chemical control requires precise timing, usually targeting first instar larvae before they burrow into fruit; mistiming reduces effectiveness significantly.
The biology study showed that oviposition peaks coincide with seasonal fruit drop and fruit size growth.
The study developed mass-rearing techniques as sufficient field-collected insects are inadequate for research.
On commercial farms, litchi moth damage is generally low to moderate and not economically significant, but proximity to other host crops can increase infestation.
Tortricid moths may oviposit on fruit already damaged physiologically or by other pests, complicating damage attribution.
The presence of coconut bug nymphs and other coreid bugs on litchis suggests additional pest damage requiring further study.
Chemical trials showed Product X had the best control, with acetamiprid and fenpropathrin also effective.
Population abundance and damage increase as the season progresses, peaking mid-December.
The study emphasizes the importance of accurate damage identification to avoid financial losses due to misattributed pest damage.
The litchi moth is a quarantine pest, restricting exports, but effective field control and proof of pest-free fruit can enable market access.