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BIOLOGICAL PEST CONTROL IN THE NEOTROPICS
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Consequences
of Pesticide Use in the Neotropics
Biological
Control Results in Specific Areass
Biological
Control Organizations
Potential
Biological Control Successes in the Neotropics
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Overview In the Neotropics , including islands of the Caribbean,
biological control represents the most economically viable, environmentally
sound and self sustaining method of insect pest control, and it has been a
source of beneficial natural enemies in California and elsewhere (Please
refer to California Research #1, #2, #3). The earliest recorded effort of classical
biological control in this region dates back to the beginning of the 19th
Century when the coccinellids, Hippodamia
convergens Guerin-Meneville
and Rhizobius ventralis (Erichson) were
introduced to Chile from California for the control of scale insects
(Gonzalez & Rojas 1966). In 1904 natural enemies were introduced into
Peru for the control of white scale, Pinnaspis
strachani (Cooley), in
cotton, and in 1980 Prospaltella
(= Encarsia) berlesi (Howard) was introduced
to Argentina to combat the white peach scale, Pseudaulacaspis pentagona
(Targioni-Tozzetti) (Hagen & Franz 1973, Altieri et al. 1999). These
efforts were supplemented by the establishment of specialized insectaries in
Mexico in 1928, Chile in 1929 and later Peru, Argentina, Brazil, Colombia and
Nicaragua. Most of this early work was concentrated on citrus pests, because
citrus had marked the beginning of biological control efforts in 1888. This
work was initiated by the Department of Biological Control, University of
California, Riverside, which was for decades a world center for mass rearing
and distribution of natural enemies of citrus pests. Other efforts were later
initiated in sugarcane, apples, peaches, olives, alfalfa, cotton and other
field crops. The principal successes in classical biological control in
the Neotropics include the citrus blackfly, Aleurocanthus woglumi
Ashby in Mexico and Central America; the sugarcane borer, Diatraea saccharalis (F.) in Cuba, Peru, Brazil and the Caribbean;
the cottony-cushion scale, Icerya
purchasi (Maskell) in Chile;
the woolly apple aphid, Eriosoma
lanigerum (Hausm.) in
Uruguay, Chile and Argentina; the black scale, Saissetia oleae
(Olivier) controlled by Aspiditophagus
(= Metaphycus) lounsbury (Howard) in Chile and
Peru, and several species of mealybugs and scale insects in various countries
(Gonzalez 1976, MacPhee et al. 1976). Interest in biological control noticeably declined for
about two decades following the advent of chemical insecticides after World
War II. However, the environmental costs associated with many organochlorine
insecticides, and the restrictions placed on residue levels of exported
meats, vegetables and fruits by markets in Europe and the United States,
precipitated a renewed interest in biological control, but mostly as a
component of Integrated Pest Management. Consequences of
Pesticide Use in the Neotropics Altieri et al. (1999) reviewed the pesticide situation in
Latin America, specifically. Between 1980 and 1984 about 430 million U.S.$
worth of pesticides were imported, with expenditures expected to triple over
the next decade, especially in Brazil, Mexico, Argentina and Colombia (Maltby
1980). Use of most organochlorine insecticides was expected to decline, but
organophosphates, carbamates and especially pyrethroids was expected to
increase, with most being imported from industrialized countries (gonzalez
1976). Cotton accounts for most of the insecticide use in Latin America at a level
of about 6 kg. of pesticide per hectare. Several years ago in El Salvador and
Guatemala, 75% of the total pesticide consumption was devoted to cotton which
received up to 35 applications per season. Such an excessive number of
treatments resulted in serious public health problems as well as ecological
disturbances. Apple and pear orchards still receive up 8-16 treatments per
season in the southern parts of this region (Chile, Argentina, Uruguay and
southern Brazil), and most fruit trees in the tropical and subtropical areas
are heavily treated for fruit fly control. Among the vegetable crops,
tomatoes and potatoes account for the greatest pesticide use (Maltby 1980). Although there has been general concern about the
environmental and public health impact of pesticides and their toxic residues
in the region, comparatively little information is available on the
dimensions of environmental contamination (Burton & Philogene 1984). This
lack has led to the belief that pesticides are not likely to cause sufficient
environmental disruption or to seriously affect the continued growth of
agriculture (Murdoch 1980). What data is available, however, contradicts this
viewpoint (Leonard 1986). Between 1971 and 1976 more than 19,000 pesticide
poisonings were reported in Central America, mostly in Guatemala and El
Salvador. In Nicaragua more than 3,000 cases of poisoning and over 400 deaths
occurred yearly from 1962-1972. In Costa Rica pesticide poisonings averaged
about 550 per year. Parathion has been largely responsible for intoxication
in many countries (Almeida & Pereira 1963). Organochlorine concentrations
in human blood, fat tissue and mothers' milk had also reached alarming levels
in many countries (ICAITI 1977). The few pesticide surveys conducted in
ecosystems of the area have basically confirmed trends observed elsewhere. In
cotton growing areas of Central America, malaria resurgence has reoccurred
mainly due to the fact that mosquitoes have developed pesticide resistance
(Leonard 1986). Residues of organochlorine insecticides have been detected in
fish and several other invertebrate species, especially in estuaries and
areas near cotton fields (Giam et al. 1971). Up to 1970 over 35 cases of
insecticide resistance had already been detected, including important cotton,
banana and stored grain pests (Gonzalez 1976). The growing use of pesticides is influenced by government
subsidies which lower the costs to farmers. In countries such as Honduras,
Colombia and Ecuador, the rate of subsidies can be as high as 45% of retail
costs (Repetto 1985). Biological
Control Results in Specific Areas Argentina.--From 1900 to 1979, 46 natural enemy species were
imported to control 21 pest species. Of these 18 became established and 14
achieved partial control and four achieved complete control. Seven of the 21
main pests targeted are under permanent biological control. Among the
successful introductions are Prospaltella
(Encarsia) berlesi against the white peach
scale, Aphelinus mali (Haldeman) against the
woolly apple aphid and Rodolia
cardinalis (Mulsant) against
the cottony-cushion scale. Brazil.--There have been several natural enemies imported into
Brazil against a limited number of hosts. Aphelinus
mali introduced in 1923 gave
substantial control of the woolly apple aphid, and P. berlesi
has achieved complete control of the white peach scale since 1921. Poor
results were obtained with the introduction of Prorops nasuta
Waterston and Tetrastichus giffardianus Silv. against the
coffee berry borer Hypothenemus
hampei (Ferris) and the
Mediterranean fruit fly, Ceratitis
capitata (Wiedemann),
respectively (Clausen 1978). Three species of tachinids Lixophaga diatraeae
(Townsend), Metagonistylum minense Townsend, and Paratheresia claripalpis (Wulp) have been
released against the sugar cane borer and are still being used in
plantations. Apanteles flavipes (Cam.) was introduced
and achieved up to 62% parasitization in south central Brazil (Macedo 1983).
In 1978 a large biological control program against cereal aphids was initiated
in southern Brazil. Fourteen species of hymenopterous parasites and two
coccinellids, Hippodamia quinquesignata Kirvy and Coccinella septempunctata L. were introduced from Europe and Chile.
Good adaptation and significant impact was observed on Sitobium avenae
(L.) by Aphidius uzbekistanicus Luzhetski and Aphidius rhophalosiphi de Stephani, and on S. avenae
and Metopolophium dirhodum (Walker) by Praon volucre (Haliday) (Gassen 1983). As of 1991 there are
active programs in cassava, soybean, coffee and cotton. Central America.--The only recorded cases of classical biological control
in this portion of Latin America are those directed against the citrus
blackfly, Aleurocanthus woglumi Ashby, which was
introduced into Panama and Costa Rico in the 1920's. Eretmocerus serius
was introduced into Panama in 1931 and to Costa Rica in 1933-34 (Clausen
1978). Since then the pest has been under excellent biological control
(Elizondo 1987). The citrus blackfly also invaded El Salvador around 1965,
and the introduction of Encarsia
opulenta in 1971 brought
about a complete control of the pest (Quezada 1974). A recent effort against
Mediterranean fruit fly was made in Costa Rica by F. Gilstrap (pers. commun.)
of Texas A. & M. University. Parasitoids from Cameroon, West Africa were
liberated in coffee plantations at Turrialba, with some field reproduction
being reported. This work which was supported by the U. S. Dept. of
Agriculture, was unfortunately terminated before a thorough appraisal could
be made. Chile.--As in other South American countries, A. mali was imported against E. lanigerum
and R. cardinalis against I.
purchasi and Icerya palmeri Riley & Howard (Hagen & Franz 1973). In
Chile between 1903-1984, ca. 66 species of beneficial insects were introduced
against several pest species of crops such as citrus, grapes, peach, apple
and potato. Forty two of these species became adapted and established. Sixty
percent of the targeted pests are under complete or substantial control, 38%
of the introduced predators and 24% of the parasitoids are responsible for
maintaining pests at relatively low population densities. Recent efforts at
the La Cruz experiment station have resulted in substantial control of
whiteflies by Amitus spiniferus (Brιthes), various
lepidopterous pests by Trichogramma
spp., alfalfa aphid Acyrthosiphon
pisum (Harris) by Aphidius smithi Sharma & Subba Rao, and Pieris brassicae
(L.) by Apanteles glomeratus (L.). It is
estimated that biological control of several pests , i.e., Aonidiella sp. and several
species of Aphididae and the purple scale, Lepidosaphes beckii
(Newmann) have saved the Chilean citrus industry ca. $US900,000 per year in
pesticide costs (Gonzalez & Rojas 1966, Zuniga 1985). Colombia.--Aphelinus
mali was introduced from the
United States in 1933 and complete control of Eriosoma lanigerum
was obtained. In neighboring Venezuela, R.
cardinalis was introduced in
1941 for control of Icerya purchasi. Recent attempts to
control Diatraea saccharalis have involved the
introduction and mass release of the Peruvian race of Paratheresia claripalpis
Wulp. which has a shorter life cycle than the native race (Hagen & Franz
1973). Cuba.--A most outstanding biological control success was the
1930 introduction of Eretmocerus
serius Silv. against the citrus
blackfly. Full economic control was rapidly attained (Hagen & Franz
1973). Mexico.--In 1935 E.
serius was introduced
against the citrus blackfly. It became established and controlled the pest
mostly in humid areas. A further search for parasitoids was made in semi-arid
regions of asia and four additional parasitoids were found and established,
three of which became dominant in both humid and dry climates. Amitus hesperidium Silvestri became by far the most effective
parasitoid, which was then extensively released in the 1950's by the newly
organized Departamento de Control Biolσgico de Defensa Agrνcola (Hagen &
Franz 1973). Several parasitoids were introduced during 1954-55 from
Hawaii for the control of the Mexican fruit fly, Anastrepha ludens
(Loew) which is native to Mexico. A large scale production program was
initiated, and in five years more than 7 million Aceratoneuromyia indica
(Silv.) were released. This parasitoid quickly became established, accounting
for parasitization of up to 80% and lowered fruit damage to about 30% in
Morelos, Oaxaca, Veracruz, Michoacαn and other states (Clausen 1978). Aphytis holoxanthus
DeBach was released against the Florida red scale Chrysomphalus aonidum
(L.) in 1957 in Morelos and infestations in citrus groves were drastically
reduced within one year. Releases in 1954 of Aphytis lepidosaphes
Compere against the purple scale also resulted in effective biological
control (Clausen 1978). In Baja California the woolly whitefly has been
controlled with parasitoids originally introduced to California. Peru.--The woolly apple aphid was controlled by A. mali and cottony-cushion scale by Rodolia cardinalis.
The black scale was controlled by three imported parasitoids from the United
States. Cotton white scale biological control was achieved with several
parasitoids once cultivation practices were altered. There have been
altogether 12 cases of successful classical biological control in Peru: one
case in cotton, five in citrus, two in olive one in alfalfa and one in sugarcane
(Aguilar 1980). The most recent successes were in the 1970's with the
introduction of Aphytis roseni DeBach and Cales noacki Howard against Selenaspidus
articulatus Morgan and Aleurothrixus floccosus (Maskell) on citrus. Aphidius smithi was also introduced against Acrythosiphon pisum
(Harris) in alfalfa. At the national insectary CICIU, the yearly production
of Trichogramma was 131
million wasps in 1976 which were distributed over ca. 1,300 ha. at a rate of
100,000 wasps per ha. (Klein Koch 1977). There were, of course, many more introductions in the
Neotropics against fruit flies, coffee berry borer, oriental fruit moth,
etc., but documentation is lacking (Clausen 1978). Countries not mentioned
sustained little biological control activity. For instance, introductions of
natural enemies in countries surrounding Uruguay resulted in complete
biological control of cottony-cushion scale and white peach scale in that
country also. Biological
Control Organizations There are few research centers totally devoted to
biological control in the Neotropics. Earlier in this century, there were
only three centers: the INTA Castelar Insectary in Argentina, INIA's
experimental substation in La Cruz, Chile and the Centro de Introducciσn y
Crνa de Insectos Utiles (CICIU) in Lima, Peru. In Argentina the U. S. Dept.
of Agriculture opened a subsidiary laboratory of biological control of weeds
in Hurlingham near Buenos Aires, which although mostly devoted to quarantine
and selectivity studies of weed herbivores for introduction into the United
States, sponsored activities which led to the successful biological control
of the water hyacinth, Eichornia
crassipes Solms by Neochetina bruchi Hust. in the La Rioja region. In 1970 the
Universidad de Tucuman established in San Miguel de Tucuman the Centro de
Investigaciones Sobre Regulaciones de Poblaciones de Organismos Nocivos
(CIRPON), a center devoted to the integrated and biological control of citrus
and soybean pests. CIRPON also conducts regular training courses in IPM,
biological control and agroecology with participation from graduates from all
over Argentina. In Brazil four laboratories and 23 multiplication units were
established by the Programa Nacional de Melhoramiento de Cana de Azucar, for
the mass rearing and release of Apanteles
flavipes and tachinid
parasitoids for sugarcane borers. Brazil's agricultural research center,
EMBRAPA, has also built insectaries and laboratory facilities in southern
Brazil to support the cereal aphid biological control program initiated in
the late 1970's. In Colombia private sugarcane plantations have organized
small insectaries for the mass rearing of sugarcane borer parasitoids and Trichogramma wasps. In Mexico,
the government established a national system (CRIA) for the mass production
of Trichogramma spp. and
other beneficial organisms. Otherwise private or government groups have
variously initiated small efforts to deal with specific pest problems.
Examples are the projects in Venezuela against Diatraea spp. which resulted in 50% damage reduction
following the introduction of Metagonistylum
minense Townsend (Clausen
1978), the releases of two predators in the Dominican Republic against the
coconut scale in 1937 (Gomez-Menor 1937), and in Colombia against cypress
sawfly (Drooz et al. 1977). There is a long and rich tradition of biological control
in Latin America, especially in Chile, Argentina, Peru, Brazil, Colombia and
Mexico. The early success of biological control of citrus pests obtained in
California triggered a number of introductions into the citrus growing areas
of the continent, thus promoting wide interest in biological control. Other
projects followed such as those in sugarcane, cotton, peaches, olives and
wheat. The current economic and social juncture in the region calls for more
lo input approaches to agriculture. Classical biological control should be at
the forefront of any sustainable agricultural development effort,
complemented by agroecosystem management schemes (i.e., intercropping, crop
rotations, cover crops), that not only aid biological control agents but that
conserve the soil and make the agroecosystems less dependent on fertilizers,
herbicides and other chemical inputs. There is a successful case of biological control of Oxydia trychiata (Guenee) in Colombia
regulated by Telenomus alsophilae Viereck from eastern North America
(Bustillo & Drooz 1977, Drooz et al. 1977). Potential Biological Control
Successes in the Neotropics A number of
economically important arthropod pests in the Neotropics could probably be controlled
with the establishment of key natural enemies. Following
is a list of such possibilities:
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