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Click) Water provides a sort of natural cover to protect the plant of rice against the lower nocturne temperature of this region. Unfortunately, the current rice ...
MOSQUITO ABATEMENT IN SPECIFIC ECOSYSTEMS: THE PIEDMONT MOSQUITO CONTROL PROJECT IN THE RICE-GROWING AREA Mosca A. and Roberto P.

Piedmont Mosquito Control - IPLA SpA [email protected] After Sicily, Piedmont is the largest region in Italy. In spite of the latitude, across the border between Piemont and Lombardy we found the main European centre for rice growing with more than 200 thousands hectares of rice-fields. The main part of this area is located in Piedmont, with a big core of about 120 thousands hectares around Casale, Vercelli and Novara, and some small nucleus near Torino and Alessandria. This is possible thanks to an abundant availability of water, supplied in particular by the alpine glaciers and that flow through an immense irrigation net that complete a wide natural river system. Click) Water provides a sort of natural cover to protect the plant of rice against the lower nocturne temperature of this region. Unfortunately, the current rice growing techniques applied in our region provide a sequence of flooding cycles that fits strictly with the development of Ochlerotatus caspius mosquito population. The consequence is the development of a great nuisance for both humans and animals in late spring and summer, with heavy impacts on local economy. In order to face this problem, in 1997, the Regional Council issued a special law on mosquito control. After ten years, on behalf of the Piedmont government, Ipla Inc., a regional public company for environmental management, started to supervise the application of this law, in particular to drive correct communications with rice-growing farmers. During 2007, Ipla has managed directly 7 of the 18 mosquito abatement projects operating in Piedmont. In particular, the main plans have been unified in order to optimise the great efforts on the rice areas, the real core of Piedmont Mosquito Control. According to this unified project, 40,000 hectares of rice-field were monitored and treated by technicians and companies directly under Ipla control. One of the most important results of Ipla management has been that, for the first time, some hundreds of farmers were directly involved in rice-fields treatment operations. In fact, farmers had to start to cooperate with the Mosquito Control Project during their usual agronomic practices according guidelines defined together by Ipla, the Rice National Bureau, and the professional organizations of growers. By local reunions, a great number of rice-growers were met to explain them the guidelines and to obtain their aid. The guidelines provides two kind of voluntary aid by growers: direct and no direct control operation. The direct control operations consist in adding insecticides in seeds or fertilizers that are spread during the normal operations of sow and fertilization. These treatments have only the product cost for the public budget, because the grower’s intervention is free. However, for the mosquito control project there is an increase of job to manage hundreds of product deliveries and to verify the correct application, as time, doses, method, etc. The no direct control consists in a different kind of water management. It is the best solution, because means “prevention” but it is very difficult to be accepted by growers. In fact, only a little idea was accepted and now only few growers have accepted it: a different management of weedy rice control. Weedy rice or red rice is a variety of rice that produces far fewer grains per plant than cultivated rice and is therefore considered a pest. Because red rice and cultivated rice are so closely related, herbicides that would kill red rice would also kill cultivated rice. Therefore, growers often decide to flood their rice-fields for at least a week before seeding to favourite the red rice germination. Than,

the young plants of red rice were killed by herbicides. During this flood, a first generation of Oc. caspius emerges. A slight modification of this practice permits best red rice germination and avoids larval hatching. In fact, thanks to the spring ordinary temperatures of this region, a simple series of short irrigations, wet enough the soil for red-rice germination, but do not permit eggs eclosion. Farmers accept easier direct control, because it does not change anything in their regular management. They have simply to add a product to the ones they spread normally in their fields. But law imposes strong limitations in choosing biocides. According to the Italian law, farmers can use biocides only to defend their crops. And unfortunately mosquitoes are not a rice-pest. So for mosquito control we can use any kind of pesticide before rice germination, in other words until seeding, whereas after rice germination we can employ only bio-insecticides. In this first year, they covered about 20,000 hectares, free from treatment costs charged on public budgets. At the same time, experimental activities were performed to optimise these kinds of treatment. For example, great attention was put in mixing liquid, granular and powder insecticides both with the rice seed and with different kinds of fertilizers. Seeds were saturated in different ways with solutions of diflubenzuron. This liquid tends to percolate through the seeds, so is preferred the use of pure products and seeding immediately after mixing. Good results have been obtained with 200 ml per hectare of a 15% diflubenzuron product. Because of the little product volume, a most homogeneous distribution is obtained showering the seeds with a can directly on the bucket for seeding. Other tests were performed to optimise the Bti carried by fertilizers. A first series of tests was completed with 200 ITU/mg granular Bti (6 Kg/ha). Because of different specific weights among the granules, the Bti spread in the field is not uniform. Only when mixing is very well done, homogeneous, thanks to the transmitted kinetic energy among granules and the floating properties of Bti, the larval mortality is acceptable. In order to obtain a good mix, Ipla signed an agreement with farmers and a fertilizer producing company. Mixing operations were done directly in the factory during the usual fertilizer mix process to combine for example urea and potassium chloride granules together. However, the results was worst than with the same dose distributed by helicopter. Another test was performed mixing fertilizer with Bti wettable powder. In this case, the mixing procedure is more difficult. The powder pastes the fertilizer best than bti granules, but the resulting mix is less homogeneous. In spite of farmers’ help, the greater numbers of treatments continue to be performed by helicopters, because a lot of infestation does not coincide with agricultural practices. Helicopters treated a total of 130,000 hectares, so 150,000 hectares were globally reached, with an average of 3.75 intervention per paddy.