First finding of a quarantine pest,Atherigona (Acritochaeta) orientalis Schiner (Diptera: Muscidae), in Korea

The invasive quarantine pest fly, Atherigona (Acritochaeta) orientalis Schiner, is observed for the first time in tomato greenhouses in Gyeongsangbuk‐do, Korea. The genus Atherigona Rondani is also newly added to Korean fauna. Allium tuberosum is listed as a new host crop for this species. Some morphological characteristics for accurate identification and host lists are given to provide plant quarantine information for pest management.     

Physico‐chemical mechanisms of resistance to shoot fly,Atherigona soccata in sorghum,Sorghum bicolor

Sorghum shoot fly, Atherigona soccata is an important pest of sorghum, and host plant resistance is one of the important components for minimizing the losses due to this pest. Therefore, we evaluated a diverse array of sorghum genotypes to identify physico‐chemical characteristics conferring resistance to A. soccata. Susceptibility to shoot fly was associated with high amounts of soluble sugars, fats, leaf surface wetness and seedling vigour; while leaf glossiness, plumule and leaf sheath pigmentation, trichome density and high tannin, Mg and Zn showed resistance to shoot fly. Stepwise regression indicated that Mg, Zn, soluble sugars, tannins, fats, leaf glossiness, leaf sheath and plumule pigmentation and trichome density explained 99.8% of the variation in shoot fly damage. Path coefficient analysis suggested that leaf glossiness, trichome density, Mg and fat content and plant plumule pigmentation can be used as markers traits to select for shoot fly resistance in sorghum.     

Leaf surface wetness in sorghum and resistance to shoot fly, Atherigona soccata: role of soil and plant water potentials

In experiments with potted plants, the relationships between soil matric potential, plant water potential and production of water droplets (leaf surface wetness) on the folded central whorl leaf of seedlings of sorghum genotypes that are either resistant or susceptible to shoot fly (Atherigona soccata) damage were investigated. Differences in soil matric potentials in the pots affected the plant water status, which in turn had profound effects on the production of water droplets on the central whorl leaf of the sorghum genotype susceptible to shoot fly. There was no consistent variation in the relationship between plant water potential and soil matric potential of resistant and susceptible sorghum genotypes. However, there was very little or practically no water droplets on the central whorl leaf of the resistant genotypes, indicating that the production of water droplets is not solely the result of internal water status of the plant. It is suggested that leaf surface wetness is genetically controlled and that an understanding of the mechanism by which water is transferred to the leaf surface will enhance breeding for resistance to shoot fly.     

Effect of planting dates and maize hybrids on the infestation with sorghum shootfly,Atherigona soccata Rondani and its effect on the yield

Abstract

Twenty maize hybrids plus local were tested for their susceptibility to major pests of sorghum shootfly, Atherigona soccata Rondani under field conditions at Sohag governorate during three planting dates (20th April, 20th May and 5th July) sown during two tested years (2004 and 2005 seasons). The investigation showed that when the sowing dates were considered irrespective of the different years or the maize hybrids it was evident that during the first planting date (20th April), the maize hybrids harboured the highest levels of infestation with sorghum shootfly, Atherigona soccata Rondani. The second planting date (20th May) was the least affected while the third planting date (5th July) received moderate levels of infestation. Results also showed that the average infestation of Atherigona soccata during both seasons was a significantly negative correlation affected by the sowing dates and maize hybrids. The yield of maize hybrids negatively correlated with percentage of infestation by Atherigona soccata. The highest yield obtained from the maize hybrids was slightly infested by Atherigona soccata and sown during the planting date of 20th May. Therefore, the second sowing date (20th May) may be recommended as a proper cultivating date for maize hybrids as it brought about reduction not only in infestation but was also a good method to reduce chemical control. Our results indicated that none of the maize hybrids evaluated were found to be resistant to Atherigona soccata attack but maize hybrids were significantly different in their susceptibility and less than of a local control to the infestation with Atherigona soccata and divided into four groups, the first one was highly susceptible including Giza Baladi; the second group was susceptible including ten maize hybrids namely, Hf 155, Bionear 3062, Bionear 30k8, Nagah 18, Watania 4, HC 326, HC 327, Nafratity, Watania 1 and Bionear; the third group was low resistance including six maize hybrids namely, Hf 122, Hf 123, Hf 129, Hc314, Hc 325 and Hc 352; while the fourth group included Hf 10, Hf 124, Hc 311and Hc 324 and moderately resisted the Atherigona soccata infestation. These may serve as a good material for growing in the areas where the pest is a problem.     

First record of the quarantine pest Atherigona (Atherigona) oryzae Malloch (Diptera: Muscidae) in Korea

Occurrence of the invasive quarantine pest fly, Atherigona (Atherigona) oryzae Malloch, is hereby recorded for the first time in Gyeongsangbuk‐do Province, Korea. Morphological characteristics for accurate identification of the species, a list of hosts, and damage patterns are described to provide plant quarantine information for pest management.     

Reduction of shoot fly damage in irrigated post-rainy season sorghum by manipulating irrigation

Soil moisture was manipulated in an attempt to control shoot fly (Atherigona soccata Rondani) incidence in irrigated post-rainy season sorghum grown under a rainout shelter (ROS) and in field conditions. After uniform irrigation at sowing, the plants were subjected to water stress at young seedling stage (7–28 days after emergence, DAE) for different lengths of time. Soil water had profound effects on the production of water droplets on the surface of the central whorl leaf of seedlings (leaf surface wetness, LSW) of sorghum genotypes. LSW, which facilitates movement of the larvae, was more drastically affected in susceptible (CSH 5) than in moderately resistant (IS 1054) sorghum genotypes. Shoot fly oviposition (infestation) and deadhearts (crop damage) were much higher in treatments with full irrigation (control) than in treatments to which less water was applied during the first 3 wk after seedling emergence. This resulted in higher plant biomass and overall grain yield in the latter treatments than in the control. Using insecticides to control shoot fly infestation, it was shown that a simple cultural practice of inducing plant stress by reduced soil moisture content during early plant growth gave the same or better control of shoot fly damage and the same or higher grain yield than insecticide-protected plots with full irrigation. Thus the costs associated with irrigation requirement and insecticide can be greatly reduced in the former management option compared with the latter. It is suggested that manipulation of soil water content during the vulnerable early stages of crop growth can reduce shoot fly damage in irrigated post-rainy season sorghum.     

Taxonomy of the genus Atherigona Rondani (Diptera: Muscidae) from Korea

The Korean shoot fly genus Atherigona Rondani is reviewed taxonomically. A total of five species was identified: A. (Acritochaeta) orientalis Schiner, A. (Atherigona) biseta Karl, A. (Atherigona) falcata (Thomson), A. (Atherigona) oryzae Malloch, and A. (Atherigona) bifurca sp. nov. Of these, A. (Atherigona) bifurca sp. nov. is new to science, and A. (Atherigona) biseta Karl and A. (Atherigona) falcata (Thomson) are reported for the first time in Korea. A key to Korean species and photographs of external features are provided.