Applicability of Mitochondrial Genes COI, COII and Nuclear Gene 18s rDNA for Diagnostics of the Eastern Fruit Fly Bactrocera dorsalis (Hendel, 1912) (Diptera, Tephritidae)

Abstract Each mitochondrion possesses a genome that encodes some of its own components. The nucleus encodes most of the mitochondrial proteins, including the polymerases and factors that regulate the expression of mitochondrial genes. Little is known about the number or location of these nuclear factors. B-A translocations were used to create dosage series for 14 different chromosome arms in maize plants with normal cytoplasm. The presence of one or more regulatory factors on a chromosome arm was indicated when variation of its dosage resulted in the alteration in the amount of a mitochondrial transcript. We used quantitative Northern analysis to assay the transcript levels of three mitochondrially encoded components of the cytochrome c oxidase complex (cox1, cox2, and cox3). Data for a nuclearly encoded component (cox5b) and for two mitochondrial genes that are unrelated to cytochrome c oxidase, ATP synthase α-subunit and 18S rRNA, were also determined. Two tissues, embryo and endosperm, were compared and most effects were found to be tissue specific. Significantly, the array of dosage effects upon mitochondrial genes was similar to what had been previously found for nuclear genes. These results support the concept that although mitochondrial genes are prokaryotic in origin, their regulation has been extensively integrated into the eukaryotic cell.

Download Full-text

Adoption and Dis-Adoption of Sustainable Agriculture: A Case of Farmers’ Innovations and Integrated Fruit Fly Management in Kenya

Agriculture ◽

10.3390/agriculture11040338 ◽

2021 ◽

Vol 11 (4) ◽

pp. 338

Author(s):

Charity M. Wangithi ◽

Beatrice W. Muriithi ◽

Raphael Belmin

Keyword(s):

Management Practices ◽

Household Head ◽

Fruit Fly ◽

Production Costs ◽

Sub Saharan Africa ◽

Bactrocera Dorsalis ◽

Major Threat ◽

Gender And Education ◽

Sub Saharan ◽

Indigenous Methods

The invasive fruit fly Bactrocera dorsalis poses a major threat to the production and trade of mango in sub-Saharan Africa. Farmers devise different innovations to manage the pest in an attempt to minimize yield loss and production costs while maximizing revenues. Using survey data obtained from Embu County, Kenya, we analyzed farmers’ knowledge and perception as regards the invasive fruit fly, their innovations for the management of the pest, and the determinants of their adoption and dis-adoption decisions of recently developed and promoted integrated pest management (IPM) technologies for suppression of the pest. The results show that farmers consider fruit flies as a major threat to mango production (99%) and primarily depend on pesticides (90%) for the management of the pest. Some farmers (35%) however use indigenous methods to manage the pest. Though farmers possess good knowledge of different IPM strategies, uptake is relatively low. The regression estimates show that continued use of IPM is positively associated with the gender and education of the household head, size of a mango orchard, knowledge on mango pests, training, contact with an extension officer, and use of at least one non-pesticide practice for fruit fly management, while IPM dis-adoption was negatively correlated with the size of the mango orchard, practice score and use of indigenous innovations for fruit fly management. We recommend enhancing farmer′s knowledge through increased access to training programs and extension services for enhanced adoption of sustainable management practices for B. dorsalis.

Download Full-text

Host Suitability Index for Polyphagous Tephritid Fruit Flies

Journal of Economic Entomology ◽

10.1093/jee/toab035 ◽

2021 ◽

Author(s):

Peter A Follett ◽

Fay E M Haynes ◽

Bernard C Dominiak

Keyword(s):

Fruit Fly ◽

Fruit Production ◽

General Purpose ◽

Fruit Flies ◽

Host Suitability ◽

Bactrocera Dorsalis ◽

Infestation Rate ◽

Suitability Index ◽

Host Status ◽

Tephritid Fruit Flies

Abstract Tephritid fruit flies are major economic pests for fruit production and are an impediment to international trade. Different host fruits are known to vary in their suitability for fruit flies to complete their life cycle. Currently, international regulatory standards that define the likely legal host status for tephritid fruit flies categorize fruits as a natural host, a conditional host, or a nonhost. For those fruits that are natural or conditional hosts, infestation rate can vary as a spectrum ranging from highly attractive fruits supporting large numbers of fruit flies to very poor hosts supporting low numbers. Here, we propose a Host Suitability Index (HSI), which divides the host status of natural and conditional hosts into five categories based on the log infestation rate (number of flies per kilogram of fruit) ranging from very poor (<0.1), poor (0.1–1.0), moderately good (1.0–10.0), good (10–100), and very good (>100). Infestation rates may be determined by field sampling or cage infestation studies. We illustrate the concept of this index using 21 papers that examine the host status of fruits in five species of polyphagous fruit flies in the Pacific region: Bactrocera tryoni Froggatt, Bactrocera dorsalis (Hendel), Bactrocera latifrons (Hendel), Zeugodacus cucurbitae (Coquillett), and Ceratitis capitata (Wiedemann) (Diptera: Tephritidae). This general-purpose index may be useful in developing systems approaches that rely on poor host status, for determining surveillance and detection protocols for potential incursions, and to guide the appropriate regulatory response during fruit fly outbreaks.

Download Full-text

Non-host status of papaya cultivars to the oriental fruit fly, Bactrocera dorsalis (Diptera: Tephritidae), in relation to the degree of fruit ripeness

International Journal of Tropical Insect Science ◽

10.1017/s1742758416000242 ◽

2016 ◽

Vol 37 (01) ◽

pp. 19-29 ◽

Cited By ~ 2

Author(s):

Domingos Cugala ◽

João Jone Jordane ◽

Sunday Ekesi

Keyword(s):

Fruit Ripening ◽

Market Access ◽

Fruit Fly ◽

Fruit Flies ◽

Bactrocera Dorsalis ◽

Laboratory Evaluation ◽

Ripening Stage ◽

Field Cage ◽

Major Barrier ◽

Ripening Stages

AbstractPhytosanitary measures are a major barrier to trade in papaya. We assessed the infestation of tephritid fruit flies on different stages of maturity of papaya, to determine its non-host stage of maturity, for market access. Papaya fruits were collected from Kilifi and Embu counties, Kenya from March 2013 to December 2014, to assess the level of infestation by fruit flies according to the degree of fruit ripening. In all locations, no fruit fly infestation was recorded on papaya when fruits were at the 0, 25 and 50% yellow fruit ripening stage.Bactrocera dorsalis(Hendel) was, however, observed attacking fruits when papaya fruits were at 75 and 100% all yellow (fully ripe fruit ripening stage) with infestations of 0.19−0.51B. dorsalis/kg fruit and 0.24−1.24B. dorsalis/kg fruit, respectively, in all locations. Field cage exposure ofB. dorsalisto fruits of five papaya cultivars—‘Papino’, ‘Neo Essence’, ‘Sunrise Solo’, ‘Tainung No. 1’ and ‘Tainung No. 2’ in Manica Province, Mozambique—showed thatB. dorsalisdid not infest fruits at 0, 25 and 50% yellow ripening stages at the densities of 50 and 100 flies per cage. However, at 75% yellow ripening stage, up to 13.1 pupae/kg of fruits was recorded at a density of 150 flies per cage in Tainung No. 1, and infestation ranged from 4.5 to 136 pupae/kg fruits at 100% yellow ripening stage across all the cultivars and infestation densities. Laboratory evaluation of volatiles emanating from freshly crushed papaya pulp of four cultivars: ‘Sunrise Solo’, ‘Red Lady’, ‘Papayi’ and ‘Apoyo’ on egg viability ofB. dorsalisshowed that at 0, 25 and 50% yellow, egg hatchability was inhibited, suggesting that semiochemical compounds present in green tissues of papaya prevent egg development, although this effect was variable across the four cultivars and ripening stages. Export papaya is harvested at less than 40% yellow ripening stage. Our results, therefore, suggest that quarantine treatment for fruits at this ripening stage is inconsequential, asB. dorsalisdoes not infest papaya fruits at this stage; thus, authorities should permit entry of these papaya cultivars of less than 40% yellow ripening stage to quarantine-sensitive markets.

Download Full-text