Abundance and Diversity of Frugivorous Fruit Flies in Kandara, Murang’a County, Kenya

Fruits and vegetables are important source of livelihood to farmers and major horticulture sub sector with high contribution to agricultural GDP in Kenya. This study was conducted to determine diversity and abundance of frugivorous fruit flies in Kandara sub county, Murang’a County in 2018, at a place where first area of low pest population was created in Kenya for Bactrocera dorsalis. Three sets of pheromone traps (Methyl-Eugenol, Cuelure and Trimedlure) were set in six trap stations within farmers’ orchards in four agro-ecological zones (LH1 (Lower Highland Zone), UM1 (Upper Mid-land Zone), UM2, and UM3). The trap catch data was collected fortnightly and data analyzed. Six fruit flies species namely; Bactrocera dorsalis, Ceratitis cosyra, Ceratitis capitata, Zeugodacus cucurbitae, Dacus bivittatus and Perilampsis sp were identified. Bactrocera dorsalis population was significantly (P<.001) different across the four agro-ecologies with lowest densities at LH1 and highest at UM3. Likewise, C. capitata recorded significant (P=0.042) difference densities across the agro-ecological zones, but no significant (P=0.386) difference was recorded for C. cosyra across the agro-ecological zones. Further, there was significant (P=0.012) difference in the number of Perilampsis sp across the agro-ecologies with the highest number recorded in UM1. Both Z. cucurbitae (P=0.061) and D. bivittatus (P=0.056) had low abundance across the agro-ecologies. The peak infestation period differed across the various fruit fly species, whereby B. dorsalis peaked in May, C. capitata in February and C. cosyra in January. The study shows that abundance for the fruit flies is probably related to their preferred hostplant and the weather patterns. We recommend continuous monitoring and intensifying trapping activities during peak periods in order to control the pest and protect fruits from damage. Farmers should be trained on the use of pheromone traps to reduce over-reliance on pesticides. Key words: Agro-ecologies, Bactrocera dorsalis, Ceratitis sp, fruit fly density, Pheromone

Interactions between Two Parasitoids of Tephritidae: Diachasmimorpha longicaudata (Ashmead) and Psyttalia cosyrae (Wilkinson) (Hymenoptera: Braconidae), under Laboratory Conditions

The braconid wasp, Diachasmimorpha longicaudata (Ashmead), was introduced in Kenya from Hawaii for classical biological control of the invasive tephritid, Bactrocera dorsalis Hendel. Following reports that D. longicaudata had formed new associations with Ceratitis cosyra, laboratory experiments were conducted to assess the interaction between the introduced and the native parasitoid of C. cosyra; Psyttalia cosyrae (Wilkinson) under three scenarios: B. dorsalis only, C. cosyra only and mixed populations of the two species. Parasitoids were introduced to the host as sole, sequential and simultaneous releases. Host searching and probing events were five times higher for D. longicaudata than P. cosyrae with both hosts. Total parasitism was highest (78%) when D. longicaudata was released alone on C. cosyra, compared to 20% for P. cosyrae released on the same host. Releases of P. cosyrae on B. dorsalis resulted in 0% parasitism, compared to 64% parasitism by D. longicaudata. Specific parasitism for P. cosyrae was three times higher when P. cosyrae was released first in sequential releases on C. cosyra compared to when it was released after D. longicaudata. These findings suggest that the two parasitoids can both suppress C. cosyra but B. dorsalis acts as a reproductive sink for P. cosyrae. Our findings should form the basis of field investigations where options are much wider for both parasitoids.

Effectiveness of Selected Parapheromones for Mass Trapping of Mango Fruit Fly, Ceratitis cosyra Walker and Oriental Fruit Fly, Bactrocera dorsalis Hendel (Diptera: Tephritidae) on Mango

Mango (Mangifera indica L.) is an important fruit crop in Nigeria. It is a source of essential vitamins and is also cultivated for its nutritional, medicinal and industrial uses. Fruit flies infest various commercial fruit crops and cause economic damage. Mass trapping and male annihilation technique (MAT) has been the most useful and common means of controlling fruit flies with special focus on Bactrocera dorsalis Hendel (Diptera: Tephritidae) on mangoes. The study evaluated the effectiveness of four types of parapheromones namely, methyl eugenol (liquid and solid forms), cuelure, terpinyl acetate and trimedlure for mass trapping of fruit flies on Mango. Modified Lynfield traps containing the parapheromones were randomly set on the mango orchards in three replicates in Nigeria Horticultural Research Institute (NIHORT) orchard, Okigwe, Imo state, Southeast Nigeria. This study was conducted during the mango fruiting period of 2019 season, when the density of fruit flies peaked. Effect of parapheromones on mean number of damaged dropped fruits was also evaluated. The mean population of B. dorsalis and Ceratitis cosyra was significantly higher (P>0.05) in liquid methyl eugenol traps when compared to other parapheromones. Bactrocera dorsalis recorded more than 90% of the fruit flies that were trapped especially in the first 3 weeks of trapping. In orchard I, Liquid methyl eugenol significantly (P<0.05) trapped highest number of B. dorsalis (270.20) in week I and similar trends were observed in orchard II. There was steady decline in damaged dropped mango fruits as the study progressed (Fig. 1 and 2). Use of liquid methyl eugenol was most effective in trapping B. dorsalis and C. cosyra, and it can be incorporated in Integrated Pest Management (IPM) programmes for the control of fruit flies.

Seasonal Spatial Distribution of the Mango Fruit Fly (Ceratitis cosyra) in Mango Trees Pruned to Give Three Different Pruning Canopies in High Density Mango Production in the South Eastern Lowveld of Zimbabwe

The mango fruit fly (Ceratitis cosyra Walker) is the major pest of economic importance and which restricts mango exports from infested production areas in the SADC region. The effect of three pruning techniques, box/rectangle, spherical/round and the central leader, on assessing spatial distribution of fruit fly populations in high density mango production were investigated at Chiredzi Research station (21°01’S, 31°33’E) from 2010 to 2013. Results showed a significant rise in the number of adult fly catches among pruning techniques as from July to December (p< 0.05). Traps baited with Malathion 25% WP with molasses as an attractant were used to trap the flies. Results from all treatments indicated a significant rise in mean adult fruit fly catches from the months of July to December. It can be concluded that spatial distribution of the mango fruit fly is influenced by the fruiting and ripening patterns of mango.