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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 (Bréthes), 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 Biológico de Defensa Agrícola (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,
Michoacán 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
Introducción y Cría 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 might be controlled with the establishment of key natural
enemies. Following is a list of such
possibilities:
The
list could unquestionably be greatly enlarged were additional studies made in
the respective areas, the present one reflecting a disproportionate attention
in Central America. REFERENCES: <bc-66.ref.htm>, <pooled.htm> [Additional
references may be found at MELVYL Library ] |