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AVOCADO SEED MOTH Stenoma catenifer Walsingham -- Leipidoptera,
Stenomidae ----- CLICK on Photo to enlarge & search for Subject Matter
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Levels of S.
catenifer infestation in avocados can be high. In some
avocado growing regions of Brazil 100% of the crop can be infested with S.
catenifer (Nava et al., 2005a), and in orchards that are
sprayed with broad spectrum insecticides 7-11 times over the course of a
single growing season up to 60% of fruit can be infested with larval S.
catenifer (Nava et al., 2005b). Consequently, this pest
is considered to be one of the major impediments to commercial avocado
production in Brazil (Nava et al., 2005a,b). In Venezuela, avocado fruit
infestation with S. catenifer larvae can
be as high as 80% (Boscán de Martínez and Godoy, 1982). Eggs and
oviposition. Stenoma catenifer eggs
are small and oval in shape (on average eggs are 0.59 ± 0.04 mm long and 0.38
± 0.2 mm wide) (Cervantes Peredo et al., 1999). Eggs are laid singly and are
initially white or pale cream when first laid and later darken as they
mature. Female moths oviposit at night with peak oviposition occurring within
four hours of darkness in which time 80% of eggs are laid (Nava et al.,
2005a). Stenoma catenifer females
tend to lay eggs on rough surfaces and in crevices such as the fruit pedicel
or necrotic spots on fruit (Hohmann et al., 2003). Oviposition studies in cages indicate
that up to 68% of oviposited eggs can be laid on the branch to which the
avocado fruit pedicel is attached (Hoddle unpublished data, 2007). In the
laboratory, caged females can be induced to lay eggs on rough quilted paper
towel as long as avocado fruit are provided as a stimulus to induce egg
laying (Nava et al., 2005a). Larvae. First instar
larvae are pale cream to a very light violet in color. As larvae pass through
successive instars they become progressively more violet in color. The final
fifth instar (up to 25 mm in length) is characterized by having violet dorsal
coloration contrasting strikingly with a blue-turquoise colored ventral
surface. When fifth instar larvae are ready to pupate the majority (>95%)
will abandon the seed or fruit within which they are feeding, initiate active
walking and climbing for approximately 12 hours, after which they will enter
a quiescent period for another ~12 hours, often in a protected spot (e.g.,
under paper towel in the lab). During this quiescent period larvae will spin
a very lose and fragile silk tent within which they will pupate. Pupae. Pupae are
“free” chrysalises that may be loosely attached with fine weak silk strands
to a substrate but can be easily dislodge with gentle prodding. In the field,
S. catenifer pupate in the soil at 0.5-2.0cm depth after leaving the fruit
they were feeding in (Boscán de Martínez and Godoy, 1984). Young pupae are a
striking turquoise blue in color and within 4-8 hrs of initial pupation this
color becomes reddish-brown as pupae mature and melonize. Male and female
pupae can be separated based on the presence of a small “suture” that divides
abdominal segment 9 in the males (Cervantes Peredo et al., 1999). Some S.
catenifer larvae (<5%) will pupate within the seed in which they were
feeding (Hoddle unpublished data). Adults. Adult moths are light tan color, and wings are
marked with numerous black spots. The most characteristic marking on the
forewings is the easily observable “C” shape of spots as the distal end of
the forewings. Adult females are about 15 mm in length (tip of head to tip of
wings) when in the resting position with wings folded across the dorsum. Wing
span for females with forewings fully spread is around 28-30 mm in breadth.
Males tend to be slightly smaller (2-3 mm shorter) than females and are
similarly colored (Hoddle unpublished data 2007). During the day, the majority of
adult S. catenifer rest in dried leaf duff, weeds, and
other litter in avocado orchards and this behavior has been recorded in more
natural forest situations as well (Cervantes et al., 1999). Flight monitoring
of 45 laboratory-reared adult S. catenifer into an
avocado orchard at 2:00pm in the afternoon revealed the following: (1) Adults
(n=15) released individually at 1.5 meters on open ground in full sun all
flew immediately into orchard weeds and dried avocado leaves and hid. (2)
Adults (n=15) released individually at 1.5 meters immediately under the shade
of an avocado canopy all flew directly to the ground and similarly hid
amongst and under dried avocado leaves or in soil cracks. (3) Adults (n=15)
released individually at ~3.5 meters of height within the canopy of avocado
trees all flew directly to the ground to seek refuge. The distance measured
for adult Stenoma flight upon
release from plastic vials ranged from 3 to 12 meters. Biocontrol Hymenoptera: Braconidae) (Nava et
al., 2005b). Ichneumonids have also been recorded from S.
catenifer larvae and include: Eudeleboea sp.,
and Pristomerus sp. (Nava et al.,
2005b). The second most important
parasitoid attacking S. catenifer in
Guatemala is a solitary braconid, Macrocentrus sp.
Adult parasitoids are dark yellow in color with brown markings. This
parasitoid causes third and fourth instar S. catenifer larvae
to abandon avocado fruit before fully maturing. A single pale colored
parasitoid larva emerges from hosts which have a contracted dehydrated
appearance. Macroncentrus larvae
spin a very distinctive beige colored and cigar shaped cocoon. In
Guatemala, the dominant larval parasitoid attacking S.
catenifer is a gregarious Apanteles sp.
which can succcessfully parasitize 50-100% of larvae. Estimates of parasitism
levels from surveys in Guatemala are affected by location, number and time
samples were taken (Hoddle unpublished data 2007). Young Apanteles sp.
larvae erupt out fifth instar S. catenifer larvae
and about 4-8 hours after emergence the majority of larvae have spun silk
cocoons. The number of parasitoid larvae emerging from S.
catenifer larvae ranges 2-27, and averages 8-9 larvae
per host. A small number of S. catenifer larvae
die in avocado seeds and parasitoids pupate within larval feeding galleries
within the avocado seed. Adult parasitoids are black with orange coxae.
The sex ratio is around 53% male and 87% of adult parasitoids successfully
emerge from cocoons. Terrestrial predators are likely to
be important natural enemies of S. catenifer because
mature S. catenifer larvae emerge from the protection
of avocado seeds to pupate in the soil and adult moths seek refuge in leaf
duff on the orchard floor during day light hours. One very common ground
predator encountered in Guatemalan avocado orchards during the day and night
was the lycosid spider Hogna sp. In
laboratory trials, this predator readily consumed larval, pupal, and
adult S. catenifer. Spiders were still alive 36 hrs
post-feeding indicating that immature and adult S. catenifer life
stages did not have any adverse intoxicating effect on these predators. REFERENCES: [Additional references may be found at: MELVYL Library ] Acevedo, E., Vasquez, J., and Sosa, C.
1972. Estudios sobre el barrendor del heuso del aguacate Stenoma
catenifer Walsingham (Lepidoptera: Stenomidae).
Agrociencia 9: 17-24. Boscán de Martínez, N. and Godoy, F.J.
1982. Apanteles sp. (Hymenoptera: Braconidae) parasito
del taladrador de fruto del aguacate Stenoma catenifer Walsingham
(Leipidoptera: Stenomidae) en Venezuela. Agronomia Tropical 32: 319-321. Boscán de Martínez, N. and Godoy, F.J.
1984. Observaciones preliminares sobre la biologia de Stenoma catenifer
Walsingham (Lepidoptera: Stenomidae) taladrador del aguacate (Persea
americana Mill.). Agronomia Tropical 34: 205-208. Cervantes Peredo, L., Lyall, C.H.C.,
and Brown, V.K. 1999. The stenomatine moth, Stenoma catenifer Walsingham:
a pre-dispersal seed predator of Greenheart (Chlorocardium rodiei [Schomb.] Rohwer, Richter and van der Werff) in
Guyana. Journal of Natural History 33: 531-542. Garcia, A.M., Villa, M.M., Gutiérrez,
A.M. 1967. El aguacate: plagas and enfermades. Fitofilo 20: 5-30. Hoddle, M.S., and C.D. Hoddle. 2008a.
Bioecology of Stenoma catenifer (Lepidoptera:
Elachistidae) and associated larval parasitoids reared from Hass avocados in
Guatemala. J. Econ. Entomol. 101: 692-698. Hoddle, M.S., and C.D. Hoddle. 2008b.
Lepidoptera and associated parasitoids attacking Hass and non-Hass avocados
in Guatemala. J. Econ. Entomol. 101: 1310-1316. Hoddle, M.S., and C.D. Hoddle. 2008c.
Aspects of the field ecology of Stenoma catenifer (Lepidoptera:
Elachistidae) infesting Hass avocados in Guatemala. Fla. Entomol. 91:
693-694. Hoddle, M.S., J.G. Millar, C.D.
Hoddle, Y. Zou, and J.S. McElfresh. 2009. Synthesis and field evaluation of
the sex pheromone of Stenoma catenifer (Lepidoptera:
Elachistidae). J. Econ. Entomol. (in press). Hoddle, M.S., J.G. Millar, C.D.
Hoddle, Y. Zou, J.S. McElfresh, and S.M. Lesch. 2009. Field optimization of
the sex pheromone of Stenoma catenifer (Lepidoptera:
Elachistidae): Evaluation of lure types, trap heights, male flight distances,
and number of traps needed per orchard for detection. Journal of Economic
Entomology (submitted). Hohmann, C.L., Dos Santos , W.J.,
Menegium, A.M. 2000. Avaliação de técnicas de manejo para o controle de
broca-do-abacate, Stenoma catenifer (Wals)
(Lepidoptera: Oecophoridae). Rev. Bras. Frutic. Jaboticabal 22: 359-363. Hohmann, C.L., Meneguim, A.M., Andrade,
E.A., Novaes, T.C., and Zandoná C. 2003. The avocado fruit
borer Stenoma catenifer (Wals.) (Lepidoptera:
Elachistidae): egg and damage distribution and parasitism. Revista Brasileria
de Fruticultura 25: 432-435. Millar, J.G., M.S. Hoddle, J.S. McElfresh,
Y. Zou, and C.D. Hoddle. 2008. (9Z)-9,13-tetradecadien-11-ynal, the sex
pheromone of the avocado seed moth, Stenoma catenifer.
Tetrahedron Letters 49: 4820-4823. Nava D.E., Parra, J.R.P.,
Diez-Rodríguez, Bento. J.M.S. 2005a.Oviposition behavior of Stenoma catenifer
(Lepidoptera: Elachistidae): chemical and physical stimuli and diel pattern
of egg laying. Annals of the Entomological Society of America 98: 409-414. Nava D.E., Parra, J.R.P., Costa, V.A.,
Guerra, T.M., and Cônsoli, F.L. (2005b). Population dynamics of Stenoma
catenifer (Lepidoptera : Elachistidae) and related
larval parasitoids in Minas Gerais, Brazil. Florida Entomologist
88: 441-446. Nava D.E., de Lara Haddad, M., and
Parra, J.R.P. 2005c. Exigências térmicas, estimativa do número de geroções de
Stenoma catenifer e comprovação de modelo em campo. Pesq. Agropec. Bras.,
Brasilia 40 : 961-967. Ventura, M.U., Destro, D., Lopes,
E.C.A., and Montalván, R. 1999. Avocado moth (Lepidoptera: Stenomidae) damage
in two avocado cultivars. Florida Entomologist 82: 625-631. |
