Environmental Engineering Reference
In-Depth Information
(Hartley, O'Connor, Waas et al. 2000; Demattê, Epiphanio and Formaggio 2003; Almeida 2006)
at the wavelengths visible to Passeriformes and Columbidae (Hart 2001). Thus, seeds blend into
the soil. In addition, the camoufl aged coating is opaque and less shiny when compared with seeds
treated with Rhodamine B. This makes them less conspicuous (Schmidt, Scheiefer and Winkler
2004; Cuthill, Steves, Sheppard et al. 2005) and, in accordance with the optimal foraging theorem,
greater energy would be required to consume and locate such seeds (Avery 2002).
In response to the number of incidents involving wild bird mortality caused by the ingestion of
seeds treated with carbofuran in the Brazilian States of São Paulo, Goiás and Paraná, research in mit-
igation started in 1981 at the Department of Forestry Science, in the Superior School of Agriculture
'Luiz de Queiroz' at the University of São Paulo. Studies were conducted up until 1983, and aimed
to protect wild birds on wheat plantations. However, the results of this work were never published,
and wild bird mortality continued.
As time wore on and avian mortality persisted, assistance was sought in 2000 by a Brazilian
agrochemical enterprise, and new research was undertaken between 2000 and 2002. In light of the
new research fi ndings, federal licences were granted by the Ministry of Health and the Brazilian
Institute of Environment and Renewable Natural Resources (IBAMA) in 2003. These licenses
allowed the commercialisation of a camoufl aged carbofuran-laced seed product which did not con-
tain Rhodamine B. This formulation is still used in Brazil to mitigate the environmental impact of
carbofuran on wild birds in rice and corn plantations.
The research conducted evaluated the avian mortality caused by conventional cultivation prac-
tices using seeds treated with carbofuran against that caused by alternate control methods. The work
has been consolidated into a doctoral thesis (Almeida 2006), which is partially published (Almeida,
Couto and Almeida 2010a; Almeida, Couto and Almeida 2010b). The work showed that seed camou-
fl age can mitigate mortality and benefi t avian species whilst controlling avian pests.
This chapter presents an evaluation of the environmental impact of conventional modes of wheat,
corn and rice cultivation used today in Brazil, on dry and ploughed soil, with an emphasis on avian
mortality caused by seeds treated with carbofuran and dyed using Rhodamine B. This chapter
also compares the environmental impacts associated with the use of carbofuran, carbosulfan and
methiocarb-treated seeds, with the latter two carbamate compounds being considered as alternatives
to carbofuran, and all coloured with Rhodamine B.
Carbosulfan (Marshal) also has insecticidal and nematicidal properties, but it is considered to
be around 20 times less toxic than carbuforan. As such, it could act as a viable chemical repellent
if birds eating just one poisoned seed were able to associate the bad taste and the symptoms of tox-
icity before dying, and hence, halt further seed consumption. While carbosulfan is a less harmful
agrotoxin than carbuforan and methiocarb (Mesurol) it is still an effi cient carbamate insecticide.
Although it causes vomiting and paralysis when ingested by birds, it has already been tested (to a
point) as a secondary chemical repellent (Calvi, Grazio, Besser et al. 1976, Dolbeer, Avery and Tobin
1994), and the hope is that it will exert its repellent effect before causing mortality. A discussion
regarding the chemical properties of carbosulfan and its effi cacy as an insecticide relative to carbo-
furan can be found in Chapter 1. Methiocarb is also a carbamate insecticide, and can be viewed as a
secondary chemical repellent since it causes vomiting and paralysis when ingested by birds (Calvi,
Grazio, Besser et al. 1976, Dolbeer, Avery and Tobin 1994).
7.2 Materials and methods
Experiments at rice and wheat plantations were performed in the southeast of Brazil in the munici-
pality of Assis (State of São Paulo), in Cambará and Floraí (State of Paraná), and in central Brazil,
in Palmeiras de Goiás (see Figure 7.1). These are all regions where farmers have reported avian
mortality due to the ingestion of seeds treated with pesticides.
Search WWH ::
Custom Search