[Edited_by_A._Ciancio,_C.N.R.,_Bari,_Italy_and_K.(Bookos.org)

AERIAL BT TREATMENTS
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Africa, or Choristoneura fumiferana (Clem.), which is often very dangerous to many
nearctic conifer stands (Lentini & Luciano, 1995; Bauce, Carisey, Dupont, & Van
Frankenhuyzen, 2004), no standard protocols are available thus far in Italy for Btk
products aimed to control main urticating lepidopteran defoliators. Data are now
available only on T. pityocampa, based on experiments proceeding from other
countries. In Italy, observations began in the 1960s (De Bellis & Cavalcaselle,
1969; Triggiani & Sidor, 1982; Currado & Brussino, 1985; Niccoli & Tiberi, 1985;
Ambrosi, Salvatori, & Zanotelli, 1993; Battisti, Longo, Tiberi, & Triggiani, 1998).
Further investigations on the capability of aerial treatments by means of
biopesticides against PPM were carried out also in other European countries,
especially in France where this species is often noxious mostly in tourist areas, i.e. in
the Maritime Alps (Demolin, Martin, & Lavanceau, 1993; Demolin & Martin, 1998;
Martin & Bonneau, 2006).
Very few data are available for the Brown Tail Moth (BTM) E. chrysorrhoea as
well as for OPM. The latter species, has spread recently northwards in Europe
convincing some EU Member States to introduce national or regional control
programmes for public health reasons (EFSA, 2009). However, only in 2008 an
experimental protocol has been issued by means of aerial spreading of Btk over
large areas. Employ doses were stated at 2.5 l/ha 1 of 12.7 BIU (Billion International
Units)/l of commercial formulation and were distributed at ultra-low volume at the
time of bud opening, against 1st and 2nd instar larvae (Roversi, 2008).
Before aerial Btk treatments are deployed, it is also useful to know the exact
time of presence of larvae, which varies normally according to the different
urticating. For instance, OPM and BTM have different larval presence. In Italy, for
the former species it is necessary to treat by the end of April or at the beginning of
May, when buds are opening and leaves growing. However, it is important to treat
larvae before they reach the third instar, when they become urticating. Early
treatments in spring are also capable to better wet the crowns inside. In fact, to reach
a good biopesticide spraying all over the new foliage it is necessary to avoid some
larval groups to escape.
For BTM, the different life cycle patterns lead to treatments in the late summer
or autumn, just before the larvae hide themselves inside winter nests. However, in
mild Mediterranean climates with mild winters where BTM can feed and survive on
mixed scrubs, treatments can be delayed to the end of autumn. As to PPM,
treatments can be performed by the end of summer, when the newly hatched larvae
start to feed on needles. The winter control of PPM is possible by means of Btk
formulations applied on third instar larvae or more (L4–L5) (Martin & Mazet,
2001). Furthermore, it is worth to remark that PPM can show different life cycle
patterns, according to the different seasonal conditions and climates. In fact, PPM
eggs can be laid sometimes also at the beginning of autumn (Battisti, 1989).
Numbers of researches have been carried out in the recent years also on the Btk
impact on non-target species, as well as on the persistence of the microbial products
in the treated environment (i.e., spores-crystal complex), or the host plant effects
(Cooke & Régnière, 1999; Appel & Schultz, 1994; Kouassi, Lorenzetti, Guertin,
Cabana, & Mauffette, 2001; Bauce, Bidon, & Berthiaume, 2002; Carisey, Bauce,
Dupont, & Miron, 2004), so that the Btk residual activity is now a key-factor in