Dr. Murai Éva szerk.: Parasitologia Hungarica 23. (Budapest, 1990)

7. In the seventh series of experiments (free choice tests simulating the field conditions) the rodents were allowed to choose between the poison-free and the poisoned bait but were offered the bait for a limited time only (96, 72, 48 and 24 hours). The effect of these conditions on the rate and time of mortality was studied. Under the least favourable conditions, i. e. when LANIRAT-B and the alternative EPA standard was given in a free choice experiment, a 100 % rodenticidal effect was observed for both rats and mice already after a one-day feeding period (Table 6 and Fig. 5). 8. In this study we could not corroborate MILLER's (1974) observation according to which male rats accept anticoagulant baits less readily than do female ones. In the free choice test the male and the female rats consumed a nearly identical amount of the poisoned bait (Table 7). CONCLUSIONS LANIRAT-B is an up-to-date, ready-to-use rodenticide bait which is highly palatable to both rats and mice. Rats and mice consume sufficient amounts of LANIRAT-B even if their usual poison-free food is also available. The laboratory experiments conducted by us have proved that LANIRAT-B resulted in 100 % mortality even if the animals consumed it only for one day. With LANIRAT-B, there is no need to use higher active ingredient concentrations for mouse killing, as mice consume 2.6 LD^Q of the bromadi- olone active ingredient even under the least favourable conditions (presence of abundant alternative food, one-day feeding of LANIRAT-B). The ready-to-use bait is highly stable and can be preserved without loss of quality for a long time. Although we had no opportunity to experiment with resistant rodents, from the studies of MARSH (1977) and REDFERN and GILL (1980) the active ingredient bromadiolone is known to be effective also against rodent species which have become tolerant or resistant to first-generation anticoagulant rodenticides (e. g. warfarin). A further advantage of rodenticides containing bromadiolone is that the risk of primary and secondary poisoning of domestic animals is relatively low (MENDENHALL and PANK, 1980). On the basis of its properties outlined above, we strongly believe that LANIRAT-B, a preparation manufactured and marketed by us, can become an ideal rodenticide for animal farms, food products factories and granaries where rodent control has always been a challenge. 143