A crescente tomada de consciência dos produtores agrícolas relativamente à problemática do uso de pesticidas, tem levado a que muitos procurem formas alternativas mais ecológicas e, muitas vezes, mais económicas de controlarem as pragas agrícolas.
Este mês a Bat Conservation Times sugere mais um biopesticida muito eficiente... Os morcegos!
A utilização de morcegos como controladores de pragas agrícolas também contribui significativamente para a sua conservação, pois permite diminuir de forma significativa a aplicação de pesticidas químicos, uma das principais ameaças à sua conservação.
(in Bat Conservation Times)
Frank Bibin, a long-time BCI member and partner, uses about 4,000 bats – rather than chemical pesticides – to help protect his pecan orchard from a rogue’s gallery of pests, especially pecan nut case bearers. Mother Earth News reports that the bats save his farm more than $1,000 a year in pesticide costs.
But, the magazine says, “economics weren’t the reason Bibin started looking for alternative pest control when his family moved to the south Georgia farm in 1994. ‘Spraying was one of the most awful experiences of my life,’ he recalls. ‘It smelled terrible. ... I wore protective clothing, masks and gloves. Still it was always splashing on me when hoses broke or spray tips clogged. We found dead birds after every spraying.’”
Now, Mother Earth News says, Bibin wants to prove that what bats have done for his pecans, they can also do for corn crops.
Bibin built his first bat house in 1996, after reading a BCI brochure about bats’ appetite for insects. It took more than two years, but 25 bats took up residence in 1998 and after that, reporter Gwen Roland writes, “he kept building [and] they kept coming. Today more than 20 bat houses host up to 4,000 bats during the warm months.
“Since each bat eats about half its weight in insects, Bibin estimates they wipe out about 50 pounds of insects each night. Within three years of the bats’ arrival, the orchard was operating insecticide-free.”
Mother Earth News reports that Bibin is so pleased with the bats’ work on his behalf that he became a spokesperson for them. He frequently speaks to school and scout groups, supervises bat-house installations and has worked with BCI for years to document the value of bats as a vital part of a pest control. Television crews from France and Britain have visited his farm, and scientists conduct research there.
Roland notes that while pecan pests affect a relatively small number of orchards, corn earworms infest thousands of acres on farms in just about every state, and great amounts of pesticides are used to combat them. A variety of research has demonstrated that Mexican free-tailed bats eat enormous amounts of these moths, which also attack cotton, and save farmers millions of dollars a year.
The magazine said Bibin received a small USDA Sustainable Agriculture Research and Education grant to plant a quarter acre of organic sweetcorn, plus a control plot nearby, to study bats’ impact.
Roland wrote that both plots were planted with early, middle and late crops of sweetcorn and monitored for corn earworm damage. Samples from the conventional plot averaged 53 percent corn earworm damage for the early crop, while Bibin’s plot had an average of 26 percent damage – roughly half as much. There was no middle or late crop at the conventional site for comparison, Roland reports, but “Bibin saw his earworm damage rise to 39 percent in the middle phase and to an average of 98 percent in the late phase, indicating the bats did not control corn earworm in the late phase.”
Brooks County Cooperative Extension Agent Johnny Whiddon told Mother Earth News that the high infestation during the late phase probably was due to a large increase in corn earworm moths at that time of the season.
Bibin says that if he were repeating the project, “we would plant the corn two weeks earlier. We would also erect a new bat house closer to the corn plot because we have observed that as bats return to their roosts through the night there appears to be increased feeding activity closer to the roost.”
O MORCEGUISMOS é um espaço inteiramente dedicado aos morcegos e pretende ser um veículo de divulgação e sensibilização. Neste espaço cabe a divulgação de projectos em curso ou concluídos, notícias, e actividades diversas.
Para além disso pretende-se que contribua para uma aproximação do público a este grupo faunístico, e que este público tome parte no aumento do conhecimento sobre morcegos em Portugal, nomeadamente através da informação sobre abrigos de que tenham conhecimento.
No futuro pretende-se ainda criar uma linha de apoio a qualquer assunto relacionado com morcegos, como seja o socorro de morcegos encontrados feridos ou a perturbação de abrigos, entre outros.
Espera-se desta forma dar um contributo importante para a conservação das espécies de morcegos portuguesas.