Pg. 35-37 Voorkoms en Alternatiewe Beheermetodes van Vrugtevlieë op Lietsjies i die Nelspruit Omgewing

Proewe is gedoen om te bepaal of vrugtevliegbesmetting in ‘n vroee stadium op lietsjievrugte waargeneem kan word. Metodes om vrugtevlieggetalle in boorde te moniteer is ge-evalueer asook die effektiwiteit van lokmiddelbespuitings. Daar is gevind dat die Natalse vrugtevlieg, Ceratitis rosa, volgens vrugtevliegvangste die dominante spesie in lietsjie boorde was. Proteienhidrolisaatlokmidde/valle se effektiwiteit as moniteringvalle vir Natalse vrugtevliee was so goed dat dit moontlik as alternatiewe beheermetode gebruik kan word. Proteienhidrolisaatlokmiddels blyk soveel meer effektief te wees as suiker dat laasgenoemde nie meer ‘n plek in vrugtevliegbeheer regverdig nie. Daar is weereens bevestig dat lokmiddeltoediening effektief is, maar dat effektiwiteit sat verhoog indien die behandelings vinniger as ‘n week op mekaar volg.

Summary:

• The study aimed to evaluate early detection methods for fruit fly infestations on litchi fruit and to assess monitoring and control strategies in Nelspruit litchi orchards.
• The Natal fruit fly (Ceratitis rosa) was found to be the dominant species responsible for most fruit fly damage in litchi orchards.
• Protein hydrolysate bait traps (Hymlure) were highly effective for monitoring Natal fruit fly populations and showed potential as an alternative control method.
• Protein hydrolysate baits were significantly more effective than sugar-based baits, which no longer justify their use in fruit fly management.
• Bait spray applications were confirmed as effective control measures, with improved efficacy when treatments were applied at intervals shorter than one week.
• Litchi fruits are not good hosts for fruit flies because secondary infections by fungi, yeasts, and bacteria through fruit fly sting sites cause fruit decay and pressure build-up, often expelling eggs and larvae before development.
• Fruit flies were monitored using parapheromone traps (Trimedlure/Capilure) attracting only males of two species (Natal and Mediterranean fruit flies), and protein hydrolysate and sugar traps attracting multiple species.
• Despite bait sprays, fruit fly numbers peaked during the fruit ripening period, with population surges linked to nearby alternate host fruits such as Koosawel.
• Early detection utilized a vacuum technique to introduce dyed water into fruit through sting punctures, enabling visualization of infestations before the fermentation process started.
• The study suggests focusing research and management efforts on preharvest control since cold storage and quarantine treatments effectively manage postharvest fruit fly risks in exported litchis.
• The article recommended frequent bait applications, more than once per week, to optimize control efficacy during peak fruit fly population periods.
• The evaluations showed that fruit fly control combining protein hydrolysate baits and regular bait sprays could enhance integrated pest management in litchi production areas.