(19.01.2012 9:13)Radek Krušina napsal(a): [ -> ]Že se spojené nádoby vyrovnávají, ta bych Gustave samozřejmě chápal.
Ale mě zarazilo právě to, že ten pokus v těch "nádobách" odhalil poměrně velký odpor.
Do dalších včelstev se z těch zamořených přeneslo pouze 2% roztočů.
Myslel jsem, že je to mnohem víc.
Proto se ptám, jesli k tomu někdo má nějaké další údaje.
Chtělo by to vědět víc.
Volně přeložený závěr: Při normáních podmínkách ve včelařství je invazní tlak mnohem vyšší. Naše výsledky ukazují nato, že zamořené včelstva představují riziko pro včelstva až na vzdálenost 1,5km. Proto je pro praktické včelařství nutné léčit koncepčně (v ČR dle metodiky) v podletí ve stejnou dobu.
Jinak k těm 2%, jak jsi naně vlastně došel? Procenta se udávají v poměru k dělnicím neléčených včelstev. To znamená, že v srpnu když začínaly pokus, připadalo na sto dospělých dělnic 18 roztočů , když pokus končil, dvě včelstva byly KO a zbytek vykazoval zamoření takové, že na 100 dospělých dělnic byl počet 38 roztočů.
Z jiných zdrojů čtu, že invaze do čistých včelstev byla zaregistrována do týdne. resp. Také že předpokládají, že hodně roztočů ubylo ve zhroucených včelstvech._gp_
Invasion of Varroa mites into mite-free colonies at a military training area. E. Frey, P. Rosenkranz (Apicultural State Institute, University of Hohenheim, 70593 Stuttgart, Germany) Honey bee colonies should be treated against varroosis in late summer to guarantee the production of healthy winter bees. However, the invasion of Varroa mites from non-treated colonies may wreck the treatment effect. To quantify the invasion rates we used a former military training area which is not accessible to other beekeepers. Four heavily Varroa infested honey bee colonies served as “donator” colonies. In distances of 1, 30, 400, 1300 and 1500 m from the donator colonies we placed two mite-free monitoring colonies each which were continuously treated with different acaricides. The “mite free status” was confirmed by the analysis of bee and brood samples. From August–October 2006 the number of Varroa mites on the bottom boards of the monitoring colonies were counted at weekly intervals to record the Varroa invasion rate. The average Varroa infestation rates of the adult bees in the “donator colonies” increased from 18% in August till 38% in October. Two colonies died at the beginning of October due to the high Varroa infestation. In total, 2029 mites were recorded in the bottom boards of the 10 monitoring colonies during the 8-week period. The average invasion rates per colony were 283 at 1 m distances from the “donator colonies”, 201 at 30 m, 155 at 400 m, 122 at 1300 m and 255 at 1500 m. Under normal beekeeping conditions the density of bee colonies and, therefore, the invasion pressure would be considerably higher. Our data confirm that highly infested colonies represent a risk for treated colonies over distances up to 1.5 km. For beekeeping practices, the treatment of all colonies at the same time during the late summer period is an urgent need for treatment concepts.
jiný zdroj:
The honey bee mite Varroa destructor can be spread between colonies by vertical transmission, particularly when heavily infested colonies are robbed by foraging bees from neighbouring hives. We quantified the invasion of V. destructor into mite free colonies on a military training area not accessible to other beekeepers. Ten "mite receiver colonies" continuously treated against V. destructor were placed at distances of one to 1.5 km from four heavily infested "mite donor colonies". Over a two month period from August to October, the population of bees, brood, and V. destructor in the donor colonies were estimated at three week intervals and the invasion of V. destructor into the receiver colonies was recorded every 7-12 days. During the experimental period, between 85 and 444 mites per colony were introduced into the receiver colonies. There were no significant differences in the invasion rates in relation to the distance between donor and receiver colonies. In total, 2,029 mites were found in the 10 receiver colonies, but these only correspond to 2.5% of the total mite population in the donor colonies at the start of the experiment. This means that the major part of the initial V. destructor population died together with the collapsed host colonies. Under natural conditions, a more benign behaviour should therefore be an adaptive strategy for V. destructor. From a practical perspective we could show that highly infested honey bee colonies present a substantial risk to already treated colonies up to distances of 1.5 km away.