Ecology and biocontrol potential of the South African flower bugs Orius thripoborus and Orius naivashae

Biological control of arthropod pests is gaining the interest of growers all over the world. Species of the genus Orius are important natural enemies of thrips and other harmful arthropods in a variety of agricultural and horticultural crops and have been widely used in biological control programmes in Europe, the Americas and Asia. In South Africa, thrips are key pests in major crops, with the sugarcane thrips, Fulmekiola serrata Kobus, as a model example. As thrips are notably difficult to control with pesticides, an effective indigenous natural enemy could provide local growers with an alternative management strategy against this pest. During surveys performed in and around South African sugarcane fields, the two little studied anthocorid predators, Orius thripoborus (Hesse) and Orius naivashae (Poppius), were selected as candidate biocontrol agents. In this dissertation, the autecology of these flower bugs was studied and their potential as biocontrol agents of thrips and other arthropod pests in South Africa was assessed based on field observations and laboratory tests. Based on our study, O. thripoborus appeared to be, in many aspects, a more suitable biocontrol agent than O. naivashae for use against arthropod pests in South Africa. Due to its better nutritional plasticity, O. thripoborus is a more easy and cheaper to rear natural enemy with an overall better predator performance compared with O. naivashae. Based on these findings, a South African company has recently started up the mass production of O. thripoborus for commercial biological control purposes in South Africa. Further research is needed to optimise the augmentative application and conservation of O. thripoborus as a biocontrol agent of thrips in sugarcane and other major crops in South Africa

Moisture source and diet affect development and reproduction of Orius thripoborus and Orius naivashae, two predatory anthocorids from southern Africa

The effect of moisture source and diet on the development and reproduction of the pirate bugs, Orius thripoborus (Hesse) and Orius naivashae (Poppius) (Hemiptera: Anthocoridae) was examined in the laboratory. Both species had been collected in and around sugarcane fields in South Africa. Supplementing eggs of the flour moth Ephestia kuehniella (Zeller) (Lepidoptera: Pyralidae) with a green bean pod as a moisture source yielded better nymphal survival and faster development, as compared with free water encapsulated in Parafilm, suggesting that the predators may extract extra nutrients from the bean pod. The impact of two factitious foods and moist honey bee pollen on developmental and reproductive parameters of both predators was also investigated. The overall performance of both Orius species on E. kuehniella eggs and cysts of brine shrimp, Artemia franciscana Kellogg (Crustacea: Artemiidae) was better than on pollen. Nonetheless, a pollen diet alone allowed 66 and 78% of the nymphs of O. thripoborus and O. naivashae, respectively, to reach adulthood. Overall, developmental and reproductive performance of O. thripoborus on the tested diets was superior to that of O. naivashae. The implications of these findings for the mass production of these predators and their potential role in biological control programs in southern Africa are discussed

Occurrence, ecology and potential impact of the New Zealand wheat bug Nysius huttoni White (Hemiptera: Lygaeidae) in Belgium

In 2002 the New Zealand wheat bug Nysius huttoni White was observed for the first time in the Netherlands and Belgium. The introduction of N. huttoni to our regions presumably occurred via overseas transport of apple and kiwi fruits from New Zealand. Laboratory experiments showed that both eggs and adults of N. huttoni were capable of surviving cold conditions similar to those in overseas transportation. Specimens were sampled in Belgium and the Netherlands, and a DNA sequence analysis indicated a 100% similarity with N. huttoni material collected in Christchurch, New Zealand. The distribution of the lygaeid in Belgium in 2008 was studied based on a systematic sampling at 105 locations. The bug had been able to spread over most of the Belgian territory, with the exception of the most southern and eastern provinces. Given the poor flight capacity of Belgian N. huttoni populations, other methods of dispersal may be involved. N. huttoni occurred primarily in ruderal habitats, and its weedy host plants belong to very common plant families. Several observations support N. huttoni not being a threat for agricultural crops in Belgium under the present conditions of climate and soil usage

Citizen science and monitoring forest pests

Purpose of the Review One of the major threats to tree health, and hence the resilience of forests and their provision of ecosystem services, is new and emerging pests. Therefore, forest health monitoring is of major importance to detect invasive, emerging and native pest outbreaks. This is usually done by foresters and forest health experts, but can also be complemented by citizen scientists. Here, we review the use of citizen science for detection and monitoring, as well as for hypothesis-driven research and evaluation of control measures as part of forest pest surveillance and research. We then examine its limitations and opportunities and make recommendations on the use of citizen science for forest pest monitoring. Recent Findings The main opportunities of citizen scientists for forest health are early warning, early detection of new pests, monitoring of impact of outbreaks and scientific research. Each domain has its own limitations, opportunities and recommendations to follow, as well as their own public engagement strategies. The development of new technologies provides many opportunities to involve citizen scientists in forest pest monitoring. To enhance the benefits of citizen scientists’ inclusion in monitoring, it is important that they are involved in the cocreation of activities. Summary Future monitoring and research may benefit from tailor-made citizen science projects to facilitate successful monitoring by citizen scientists and expand their practice to countries where the forest health sector is less developed. In this sense, citizen scientists can help understand and detect outbreaks of new pests and avoid problems in the future

Diapause and winter survival of two Orius species from southern Africa

The cold hardiness and overwintering potential of the southern African pirate bugs, Orius thripoborus (Hesse) and Orius naivashae (Poppius) (Hemiptera: Anthocoridae), were assessed in the laboratory. Diapause traits were studied by observing nymphal development and reproductive performance of adults at 18 A degrees C and three photoperiods (10:14, 12:12 and 14:10 (L:D) h). A 12 h light regime was also tested at 23 A degrees C. A 12 h photoperiod and 18 A degrees C induced reproductive diapause in 84 and 42 % of O. naivashae and O. thripoborus females, respectively. Cold tolerance of adults was measured by determining the supercooling point (SCP, the temperature at which the insect's body fluids freeze) and lethal time (LT50, the time required to kill 50 % of the population) at 0 and 5 A degrees C. All observed SCPs ranged from -21 to -17 A degrees C. Significantly lower SCP values were observed for acclimated (seven days at 10 A degrees C) O. naivashae females. LT50-values averaged 6.4 and 4.4 days at 0 A degrees C and 11.6 and 7.8 days at 5 A degrees C, for adults of O. thripoborus and O. naivashae, respectively. The findings indicate that O. naivashae is less cold tolerant and has a higher diapause incidence compared with O. thripoborus. Therefore, the latter species may have better potential for use in biological control programmes in the cooler regions of southern Africa or elsewhere

Thermal biology of the predatory bugs Orius thripoborus and O. naivashae (Hemiptera: Anthocoridae)

Developmental and reproductive traits of two little studied anthocorid predators from southern Africa, Orius thripoborus (Hesse) and Orius naivashae (Poppius), were examined at several constant temperatures. Development was studied at 12, 15, 23, 25, 29, 33, and 35 degrees C. Eggs of both species did not hatch at 12 degrees C. Nymphal survival was poor at 15 degrees C for O. naivashae, and at 33 degrees C and 35 degrees C for O. thripoborus. Total development time of males and females decreased with increasing temperature. Based on a linear degree-day (DD) model, lower threshold temperatures for egg and nymphal development were estimated to be 9.4 and 10.2 degrees C for O. thripoborus, and 11.3 and 11.8 degrees C for O. naivashae. Thermal requirements for these stages were 73.8 and 191.1 DD, and 65.2 and 168.2 DD, respectively. Adult reproduction was studied at 15, 19, 25, and 33 degrees C. Highest lifetime fecundities for O. thripoborus and O. naivashae were found at 25 degrees C. At 15 degrees C, half of the O. thripoborus females oviposited, whereas O. naivashae females only produced infertile eggs. At 33 degrees C, however, most of the O. naivashae females produced eggs, whereas O. thripoborus females did not oviposit. Our observations suggest that O. thripoborus is adapted to a slightly cooler temperature range as compared with O. naivashae. The complementarity of both predators in terms of their temperature adaptation opens possibilities for their use in biological control programs at different times of the season

Eggs of Ephestia kuehniella and Ceratitis capitata, and motile stages of the astigmatid mitesTyrophagus putrescentiaeand Carpoglyphus lactis as factitious foods for Orius spp.

Several factitious foods were assessed for rearing the anthocorid predators Orius thripoborus (Hesse) and Orius naivashae (Poppius) (Hemiptera: Anthocoridae) in the laboratory. Developmental and reproductive traits of both Orius species were examined when offered frozen eggs of the Mediterranean flour moth, Ephestia kuehniella Zeller, frozen processed eggs of the medfly, Ceratitis capitata Wiedemann, or mixed motile stages of the astigmatid mites Tyrophagus putrescentiae (Schrank) or Carpoglyphus lactis (L). Whereas C. lactis and T. putresecentiae proved to be an inferior food for rearing O. thripoborus and O. naivashae, eggs of C. capitata fully supported development and reproduction of both predators. Results on medfly eggs were similar or slightly inferior to those on E. kuehniella eggs, which is the standard food for culturing these anthocorid bugs. O. thripoborus could be maintained for 4 consecutive generations on C. capitata eggs indicating that processed medfly eggs can be a suitable and cheaper alternative to E. kuehniella eggs for prolonged rearing of these Orius spp

Supplementation of an artificial medium for the parasitoid exorista larvarum (Diptera: Tachnidae) with hemolymph of Hermetia illucens (Diptera: Stratiomyidae) or Antheraea pernyi (Lepidoptera: Saturniidae)

The effect of supplementing hemolymph of the black soldier fly, Hermetia illucens ( L.), or the Chinese oak silkworm, Antheraea pernyi ( Gue ' rin- Me ' neville), to a basic insect- free artificial medium for the tachinid Exorista larvarum ( L.) was investigated. The supplementation ( 20% w/ w) was based on the assumption that insect additives may optimize the media for this parasitoid. Egg hatch, pupal and adult yields, and sex ratio did not differ among the enriched and basic media. Preimaginal development was faster on both hemolymph- enriched media than on the basic medium. Despite the shorter development on the medium supplemented with H. illucens hemolymph than on the basic medium, on the two media puparium weights were comparable. The female flies reared on the medium enriched with H. illucens hemolymph did not lay more eggs, but the latter yielded significantly more puparia compared with the control females. Conversely, the medium enriched with A. pernyi hemolymph yielded lower female puparium weights than the basic medium and produced only one ovipositing female out of the five obtained female adults. These results indicate that the in vitro development of E. larvarum improved when the basic artificial medium was enriched with H. illucens hemolymph, whereas the supplementation with A. pernyi hemolymph negatively affected the quality of the in vitro- reared females