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Dispersal of eriophyoid mites is crucial for the successful colonization of new plants. Literature suggests that their long-distance dispersal is through aerial transfer. During dispersal, eriophyoids might be captured in vapor or fine drops of water (perhaps most likely in clouds) where they might be protected against water loss and desiccation, but where they would have no food and be exposed to low temperatures and oxygen concentrations. Considerable resistance of these mites to these stressful environmental conditions is expected and has only partly been confirmed experimentally. The aim of the bioassays conducted here was to assess the survival of five eriophyoid species off their host plants, with poor oxygen availability under two temperature regimes. The bioassays were carried out on live mites dipped into two media used as microenvironments: (1) vaseline oil (used also as control treatment), and (2) water solution of Tween 80 (0.2%) and cycloheximide (50 mg/l). The bioassays were performed at 5 ± 1 and 25 ± 1 °C. The survival of mites was assessed weekly (5 °C) or daily (25 °C) by counting live and active specimens. The following species were subjected to the bioassays: Aceria caulobia (a stem gall mite), Aceria ficus (a vagrant mite), Cecidophyopsis hendersoni (a vagrant mite), Colomerus vitis (protogyne/male population and deutogyne morphs; a leaf gall mite) and Phytoptus avellanae (a bud gall mite). The survival rate of the mites was higher at 5 °C than at 25 °C under both experimental conditions. At 5 °C, the survival of almost all species was higher in the water solution (up to 6-7 weeks) than in vaseline oil (3-5 weeks). Longer survival was found for A. caulobia and P. avellanae (gall-making species) than for C. hendersoni and A. ficus (vagrant species). As expected, the deutogynes of C. vitis survived longer than its protogynes. The current results suggest that individuals of some of the tested species are well suited for withstanding cold, starvation and low oxygen rates, which could be found at higher atmospheric layers, within the clouds, allowing them an effective long-distance dispersal.

Hazelnut is a traditional crop of Georgia, where hazelnut growing is enlarging and export is increasing. Samegrelo is the main hazelnut producing region of the country. Unfortunately, different species of insect and mite pests have been detected in the orchards of this region, which cause quality and yield reduction of this valuable crop. In this paper we present the results of a study carried out in five villages of Samegrelo region where we surveyed the incidence of important pests. The three main pests: ambrosia beetle (Xyleborus dispar), bud mite (Phytoptus avellanae) and hazel long-horned beetle (Oberea linearis) were surveyed. X. dispar was widespread and caused considerable damage to hazelnut orchards in all five villages, while P. avellanae and O. linearis were detected in only three of the surveyed orchards. The mean number of abnormal buds and shoots damaged by these pests was not significantly different among the investigated orchards. The locations, surveying details and amount of damage is presented.

Eriophyoid big bud mites are key pests of hazelnuts throughout the world although little is known of the identity and impact of the species on New Zealand hazelnut crops The objective of this study was to determine the efficacy of and optimum timing for sulphur application to control these mites A field experiment tested the application of sulphur (112 g ai/tree) at 3 62 and 88 accumulated mite emergence from overwintering big buds The greatest reduction in emerging mite numbers was achieved with an application at 62 emergence The importance of determining peak mite emergence the appearance of hazelnut buds and weather conditions to optimise the time to apply control measures are discussed

5th International Congress on Hazelnut -- AUG 27-31, 2000 -- CORVALLIS, OR WOS: 000173565900072 Surveys conducted in hazelnut orchards in Samsun province during 1997-1998 showed that the most important and widespread pests were nut weevil (Curculio nucum), ambrosia beetle (Xyleborus dispar), big bud mites (Phytoptus avellanae and Cecidophyopsis vermiformis) and hazel longhorned beetle (Obera linearis). Pest populations varied over the four districts. Nut weevil adults appeared from early May to late June, and population density varied between 1-8 adults/10 "ocak". Carsamba and Salipazari districts had higher populations than the other two districts, and mean nut damage was nearly 14%. Big bud mites were widespread and were found in high populations. Big bud numbers varied from one to 7 per trunk, and Ondokuzmayis district had the highest population. Ambrosia beetle was a very serious problem in the Carsamba and Terme districts. Ambrosia beetle adults were seen in late April and early June. Hazel longhorned beetle produced very serious damage in Carsamba, Terme and Salipazari districts and numbers of injured twigs varied between 5-14 per "ocak". Pentatomid bugs (Hemiptera: Pentatomidae), fall webworm (Hyphantria cunea), filbert aphid (Myzocallis coryli), brown scale (Parthenolecanium corni, P. rufulum) and Gypsonema dealbana were found as secondary pests at varying population densities: Int Soc Hort Sci, Oregon State Univ, Coll Agr Sci, Assoc Oregon Hazelnut Ind

The hazelnut (Corylus avellana L.) agroecosystem includes several groups of harmful and beneficial organisms. This paper lists the mite species that have been recorded on hazelnut in Turkey, based on the collections of the authors as well as bibliographical sources, and gives the distribution and economic importance of each species. Forty-five mite species belonging to 20 families were found. The most common and important pest was Phytoptus avellanae Nal., present as both .gall. and .vagrant. forms. Cecidophyopsis vermiformis (Nal.) was also common in hazelnut orchards but has less economic impact than P. avellanae. Tetranycopsis horridus (Can. &Fanz.) was also important, but only on a local scale. Minor pests, widespread but not important, included Aculus comatus (Nal.), Tegonotus depressus Nal., Coptophylla lamimani (Keifer), Anthocoptes loricatus Nal., Eotetranychus coryli (Reck) and Tetranychus sp. The beneficial mite fauna was also rich, including 23 species of predatory mites, the most common of which was Kampimodromus aberrans (Oud.). Additionally, Czenspinskia transversostriata (Oud.) and Tarsonemus stammeri Schaarschmidt are reported for the first time in Turkey.

4th International Symposium on Hazelnut -- JUL 30-AUG 02, 1996 -- ORDU, TURKEY WOS: 000071757700070 Damage types caused by two forms of Phytoptus avellanae Nal. ("gall" and "vagrant" forms) and Cecidophyopsis vermiformis Nal., all of which are commonly found in the hazelnut cultivars in the Blacksea Region, were investigated by periodic sampling. Our results show that the gall form of P. avellanae feeds exclusively on generative buds and causes formation of big buds; whereas the vagrant form of P. avellanae does not cause big bud formation, but feeds intensively on both vegetative and generative buds, on catkins and on young fruit clusters which eventually fall. On the other hand, C. vermiformis itself does not cause formation of big buds, but feeds in big buds created by P. avellanae, and not all big buds are infested with C. vermiformis, Big buds with only P. ave(lanae inside have been termed "spring big buds". Due to intensive feeding and reproduction by C. vermiformis, infested big buds prematurely open and fall down at the end of summer, thus leading to the formation of "summer big buds". The nymphs and adults migrate to spring big buds after the summer big buds dry and form "winter big buds". In addition, C. vermiformis rarely infests vegetative and generative parts which may fall if infestation becomes too heavy. Int Soc Hort Sci, Working Grp Nuts

Eriophyoid big bud mites are key pests of hazelnut throughout the world, but they are difficult to control with chemicals or other methods because they are protected inside the bud. The most effective time for control is during the relatively short emergence period which is difficult for growers to predict. The key objectives of this study were to monitor mite emergence from big buds in spring, determine the phenology of mites in relation to tree phenology and weather, and identify the optimum timing for control measures. Mite emergence was found to occur between early and late spring in Canterbury, New Zealand. Mite emergence and movement occurred when daily maximum temperatures were15 degrees C and when mean temperatures were9 degrees C, with mite emergence increasing with temperature. The developmental status of new buds during mite emergence was a crucial factor in the infestation of new buds. An accumulated heat sum model (DD), starting at Julian date 152 and using a lower threshold temperature of 6 degrees C, predicted the onset of emergence on two cultivars and at two sites at approximately 172 DD. A regression model based on leaf number, bud length, bud width, DD and Julian date provided a more satisfactory prediction of percent accumulated mite emergence. It is recommended both peak mite emergence and the developmental status of hazelnut buds be used to optimise the time to apply control measures. The optimum time to apply a control was predicted to be before buds measure 0.5 x 0.5 mm (width x length), are enclosed within the axil, and have a rounded tip, or, when 50% accumulated mite emergence has occurred, whichever occurs first.

6th International Congress on Hazelnut -- JUN 14-18, 2004 -- Tarragona Reus, SPAIN Ozman-Sullivan, Sebahat/0000-0001-5240-8110 WOS: 000233635700054 The big bud mites Phytoptus avellanae Nal. and Cecidophyopsis vermifomis Nal. cause significant yield loss in hazelnut (Corylus avellana L.) orchards. Determination of effective pesticides and the proper timing of their application against big bud mites were studied in the Samsun province of Turkey. Two field trials were conducted from 1994 to 1997. The migration period of the mites (April-May) was covered each year. Nine pesticides (Sulphur WP, Azinphos-methyl EC, Azinphos-methyl WP, Dimethoate EC, Bromopropylate EC, Amitraz EC, Quinomethionate WP, Carbosulfan EC and Methidathion EC) were evaluated at their registered application rates as alternatives to the standard pesticide Endosulfan EC. Sulphur 80% WP was as effective (83.25%) as Endosulfan 35% EC (83.35%) for the control of big bud mites. A single application of Sulphur 80% WP (400 g/100 L) at the end of April or beginning of May, just before the peak period of mite migration from old big buds to new buds, was very effective in keeping mite and big bud numbers low.

5th International Congress on Hazelnut -- AUG 27-31, 2000 -- CORVALLIS, OR WOS: 000173565900063 Insect and mite pests are serious problems in Turkish hazelnut orchards and constitute a major impediment to hazelnut production. Although there are hundreds of pest species, only ten of them are common and cause economic damage. The amount of damage varies over regions and years. In addition to pest species, almost 130 natural enemy species have been found. Most growers use chemicals to control pests, and the number of applications ranges from one to four. This causes a decrease in the effectiveness of natural enemies, an increase in environmental contamination and other well-known problems. On the other hand, some farmers use neither chemicals nor other pest-control measures, and some pests have become more serious in recent years. In this paper, the development and improvement of Integrated Pest Management programs for Turkish hazelnut orchards are discussed. Int Soc Hort Sci, Oregon State Univ, Coll Agr Sci, Assoc Oregon Hazelnut Ind

4th International Symposium on Hazelnut -- JUL 30-AUG 02, 1996 -- ORDU, TURKEY Ozman-Sullivan, Sebahat/0000-0001-5240-8110 WOS: 000071757700065 During 1992-1994 we have investigated in detail the life cycles of the two forms of Phytoptus avellanae Nal. ("gall" and "vagrant" forms) and of Cecidophyopsis vermifomris Nal. which cause serious worldwide damage in hazelnut cultivars. Selected hazelnut plantations from the Blacksea Region of Turkey were visited every 2-3 days during the migration period, once every two weeks during the winter months and weekly for the rest of the year and samples were collected. The gall form of P. avellanae has a single nymph form and a simple life cycle. In spring, nymphs migrate from old big buds to healthy buds where feeding and reproduction continues until the following spring. Since the entire population is stationary within the same bud throughout the year, generations overlap. The vagrant form of P. avellanae has a different and rather complex life cycle and two forms of nymphs are present. The vagrant form feeds not only on big buds but also on vegetative and generative parts such as leaves, male and female flowers and completes its life cycle even in the absence of big buds. C. vermiformis also has a complex life cycle with two migration periods in spring and autumn. It lives inside the big buds created by P. avellanae and its generations overlap. C. vermiformis is rarely found on male and female flowers and vegetative buds. Int Soc Hort Sci, Working Grp Nuts

4th International Symposium on Hazelnut -- JUL 30-AUG 02, 1996 -- ORDU, TURKEY Ozman-Sullivan, Sebahat/0000-0001-5240-8110 WOS: 000071757700067 Phytoptus avellanae Nal. and Cecidophyopsis vermifomris Nal. commonly infest hazelnut plantations in the Blacksea Region. This study was performed on Tombul and Uzunmusa cultivars with periodic sampling during 1992-1994, in Samsun. Population fluctuations of the two species were investigated on big buds which contained either eggs, nymphs, adults of both species together or P. avellanae only. Although the numbers of P. avellanae in newly infested buds are very low in early summer, they reach maximum population levels during the following spring. C. vermiformis inside the summer big buds reaches the maximum population level in early autumn while C. vermiformis inside the winter big buds reaches the maximum population level in spring. In summer big buds infested by both species, the two populations are approximately equal in early summer whereas C. vermiformis becomes the dominant species from the end of July onwards. In winter big buds, although the number of C. vermiformis entering the big buds is low in autumn, C. vermiformis is usually the predominant population in spring. Int Soc Hort Sci, Working Grp Nuts