Semiochemistry of Pentatomoidea 683
also finding that the C. hilaris pheromone was not attractive, at least under the conditions in which it was
tested. Consequently, methyl (2E,4E,6Z)-2,4,6-decatrienoate is suggested as the best available lure for
monitoring this species.
15.2.4 Chlorochroa sayi (Stål), Chlorochroa uhleri (Stål), and Chlorochroa
ligata (Say) [Pentatomidae: Pentatominae: Nezarini]
Chlorochroa is primarily a New World genus with about 35 known species, several of which are occa-
sional pests of fruit and field crops in the western United States (Millar et al. 2010, Rider 2015). Ho and
Millar (2001a, b) identified the pheromones for three species, Chlorochroa ligata, C. sayi, and C. uhleri.
Millar et al. (2010) carried out field trials with reconstructed blends of the male-produced compounds
using custom-made cylindrical screen traps. In each case, males as well as females were trapped, although
only females had responded to these compounds in laboratory bioassays (Ho and Millar 2001a, b). The
field trials confirmed the previously reported findings of Ho and Millar (2001b) that the main component
of the C. uhleri male-specific volatiles, methyl (3R, 6 E)-2,3-dihydrofarnesoate (deployed as the racemic
methyl (6E)-2,3-dihydrofarnesoate), was the only component attractive to adults in field assays. Addition
of the two minor male-produced components did not affect catches nor did addition of synthetic odors of
alfalfa, a host plant. When C. uhleri pheromone was combined with both the 3-component pheromone
of C. sayi and the single-component pheromone of Nezara viridula, trap captures were reduced, indicat-
ing interference by one or both of these pheromones. For C. sayi, all three components of its pheromone
(methyl geranate, methyl citronellate, and methyl (6E)-2,3-dihydrofarnesoate) were required for maxi-
mal attraction. In contrast to C. uhleri, captures of male and female C. sayi were enhanced, not reduced,
by combination with C. uhleri and N. viridula pheromones, compared to its 3-component pheromone
alone (Millar et al. 2010). These results highlight the asymmetry of cross-species attraction as well as
the complexity in determining the attraction of males and females to different blends of pheromones and
other components in laboratory versus field bioassays. Furthermore, for the C. sayi components, differ-
ences in volatility produced varying ratios of pheromone components as the multicomponent lure aged
in the field, highlighting the challenges in obtaining stable semiochemical release ratios from lures for
extended periods of time.
15.2.5 Edessa meditabunda (F.) [Pentatomidae: Edessinae]
The genus Edessa is one of the largest in the Pentatomidae, containing approximately 260 described
species, but information on possible pheromonal communication in these species is sparse. Zarbin et al.
( 2012 ) identified a male-produced sex pheromone from Edessa meditabunda, a major pest of soybeans
in Brazil, as methyl 4,8,12-trimethylpentadecanoate ( 5 ) (Figure 15.2). The absolute configuration of
the pheromone has not been determined. Methyl 4,8,12-trimethyltetradecanoate also was present as a
minor component in the volatiles collected from males, but it did not elicit electroantennogram responses
nor did it improve attraction of females to 5 in a laboratory assay. Therefore, it does not appear to be a
component of the pheromone. Ester 5 bears strong similarities to methyl 2,6,10-trimethyltridecanoate
and methyl 2,6,10-trimethyldodecanoate, sex pheromone components of Euschistus heros (Aldrich et al.
O
6(^95) (7.9%)
78
ab
Br
Br
Br
b
c
O
O
FIGURE 15.2 Non-stereoselective synthesis of male-produced sex pheromone of Edessa meditabunda. a) 1. C 3 H 7 MgBr,
- HBr; b) 1. Mg, 2. 6 , 3. HBr; c) 1. NaOAc/HMPA, 2. H 2 /Pd, 3. LiAlH 4 , 4. CrO 3 , 5. CH 2 N 2.