Buenos Aires, Argentina
Buenos Aires, Argentina
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Wheeler G.S.,U.S. Department of Agriculture | Manrique V.,University of Florida | Overholt W.A.,University of Florida | McKay F.,FuEDEI | Dyer K.,U.S. Department of Agriculture
Entomologia Experimentalis et Applicata | Year: 2017

Brazilian peppertree, Schinus terebinthifolia Raddi (Anacardiaceae), is an invasive weed of natural and agricultural areas of Florida, Hawaii, and Texas (USA). Biological control presents an environmentally safe and cost-effective control method for invasive populations of this weed. Though many potential agents have been tested for specificity, nearly all have been rejected due to a broad host range. However, one species, a thrips Pseudophilothrips ichini (Hood) (Thysanoptera: Phlaeothripidae), shows promise from field observations and quarantine host range tests. A series of no-choice, choice, and multiple-generation tests was conducted on 127 plant taxa (including five mango and four pistachio varieties) from 45 families and 33 orders. In no-choice starvation tests, the thrips fed and produced offspring on the target weed (124 F1 adults per plant), whereas no or few (<4 F1 adults per plant) were obtained on non-target species. The primary exception was another exotic invasive tree Schinus molle L., on which an average 20 F1 thrips adults were produced. No-choice tests indicated that small numbers of F1 offspring were produced on nine other non-target plant species. The numbers of F1 offspring produced on these plants were <3% of those produced on the target weed. In choice tests, on average two or fewer F1 adults were produced on four non-target species tested, compared with 64 F1 adults on the target weed. Multiple-generation tests indicated that three generations of thrips were maintained only on the target weed and S. molle with no differences between these two plant species or across generations. Thus, this thrips species has a narrow host range that includes the two invasive Schinus spp. tested here. If released, the thrips P. ichini will constitute safe and potentially effective biological control of Brazilian peppertree in North America and Hawaii. © 2016 The Netherlands Entomological Society

Gonalons C.M.,Grupo de Estudio de Insectos Sociales | Varone L.,FuEDEI | Logarzo G.,FuEDEI | Guala M.,FuEDEI | And 3 more authors.
Florida Entomologist | Year: 2014

The cactus moth, Cactoblastis cactorum (Berg) (Lepidoptera: Pyralidae), is a pest that threatens native Opuntia spp. in North America. Control tactics developed and implemented against this invasive pest successfully eradicated the moth in Mexico and on barrier islands in the United States. However, with the cancellation of the regional management program in the United States, no control tactics are being implemented to mitigate the expansion of the moth's geographical range. Hence, an integrated approach including biological control is proposed to regulate the population of C. cactorum in North America. Field surveys of the recently described parasitoid, Apanteles opuntiarum Martínez & Berta, were carried out within the C. cactorum native range in Argentina, and laboratory studies were conducted to develop a parasitoid rearing protocol. Apanteles opuntiarum was the most common parasitoid of C. cactorum and their field distributions were similar. In the laboratory, the parasitoid's reproductive success was maximized when one or two female wasps were exposed to 30 host larvae within a 500 ml container. Laboratory reared females were less successful at parasitizing hosts than field collected females. In spite of the success achieved with laboratory rearing, male bias was observed throughout the experiments. Because this bias might be related to the presence of the reproductive parasite Wolbachia, both laboratory colony and field collected individuals were screened and Wolbachia was detected. This study provides useful field and laboratory information on (1) laboratory rearing techniques for A. opuntiarum; (2) developing host specificity test protocols for studies under quarantine conditions; and (3) selecting parasitoid populations that best match the climatic conditions present in the C. cactorum invaded areas of North America. © Florida Entomologist 2014.

Wheeler G.S.,U.S. Department of Agriculture | Mc Kay F.,FuEDEI | Vitorino M.D.,Regional University of Blumenau | Manrique V.,University of Florida | And 4 more authors.
Southeastern Naturalist | Year: 2016

Schinus terebinthifolia (Brazilian Peppertree) is a South American plant that has become invasive in many countries around the world. It was introduced into the US about 100 years ago as an ornamental. Escaping cultivation, it now occurs in Alabama, Florida, Georgia, Texas, California, and Hawai'i. This species is one of the most invasive weeds threatening agriculture and natural areas in the Southeast. Efforts to manage Brazilian Peppertree populations with biological controls began in Hawai'i in the 1950s and resulted in the release of 3 insect species. However, the control agents have had minimal impact, and the weed continues to be a difficult problem. More recently, our international team of collaborators has discovered and tested numerous new species of potential biological control agents. These species attack different plant tissues and include defoliators, sap-suckers, stem borers, and leaf- and stem-gall formers. Despite difficulty finding an agent sufficiently specific for field release in Florida, we have narrowed the field to 2 promising species, the thrips Pseudophilothrips ichini (Hood) and the foliage-gall former Calophya latiforceps Burckhardt. Results of no-choice and choice trials conducted overseas and in quarantine indicate that both species will safely contribute to the control of this invasive weed. Herbivorous feeding by immature and adult individuals of both herbivore species stunt growth, distort leaves, and should reduce reproductive output of Brazilian Peppertree.

Varone L.,FuEDEI | Logarzo G.A.,FuEDEI | Briano J.A.,FuEDEI | Hight S.D.,U.S. Department of Agriculture | Carpenter J.E.,U.S. Department of Agriculture
Biological Invasions | Year: 2014

A central aspect in biology and ecology is to determine the combination of factors that influence the distribution of species. In the case of herbivorous insects, the distribution of herbivorous species is necessarily associated with their host plants, a pattern often referred to as “host use”. Novel interactions that arise during a biological invasion can have important effects on the dynamics of that invasion, especially if it is driven by only a subset of the genetic diversity of the invading species. This is the case of the wellknown South American cactus moth, Cactoblastis cactorum, a successfully used biological control agent of non-native Opuntia cacti in Australia and South Africa, but now threatening unique cactus diversity and agriculture in North America. We studied the patterns of host plant usage by and host plant availability for C. cactorum under field conditions in Argentina, covering the geographical range of the four C. cactorum phylogroups and the recently documented southern distribution. We also assessed female preference and larval performance under laboratory conditions. Cactoblastis cactorum showed a geographical pattern of host use in its native range that was related to host availability. Laboratory assays of female preference showed some degree of preference to oviposit on O. ficus-indica, O. leucotricha and O. quimilo, but it was not positively correlated with the performance of larvae. These findings contribute to the further comprehension of the host use dynamics of C. cactorum in the insects’ native range, and could provide useful information for assessing the risk and future spread of this insect in North America. © 2014, Springer International Publishing Switzerland.

Wheeler G.S.,U.S. Department of Agriculture | Silverson N.,225 College Avenue | Dyer K.,U.S. Department of Agriculture | Kay F.M.,Fuedei
Florida Entomologist | Year: 2016

Brazilian peppertree, Schinus terebinthifolia Raddi (Sapindales: Anacardiaceae), is one of the most invasive weeds in Florida and Hawaii. In the invaded range, this fast-growing weed from South America poses a threat to agriculture and cattle production and decreases the biodiveristy of natural areas. The thrips Pseudophilothrips ichini (Hood) (Thysanoptera: Phlaeothripidae) is being studied as a potential agent for the biological control of this weed. The laboratory life history and native range of P. ichini in Brazil were examined over 10 yr. The thrips life history includes 2 feeding larval stages that occur on the plant and 3 non-feeding pupal stages that occur in the soil. Development time, body length, and distinct features of each life stage are described. The larva-to-adult development required 20 d, and adults lived for an average of 50 d. Pseudophilothrips ichini had a wide latitudinal range in Brazil along the eastern coast from Bahia (11.4°S) south to Santa Catarina State (27.1°S). It was collected from sea level to 1,329 m elevation. Observations in Brazil indicated that this thrips occurs year round and may occasionally reach high densities (>20 thrips/leaf). Despite searches in its native range of related plants, the thrips was found only on Brazilian peppertree. Considering the short generation time, broad environmental tolerance, host specificity, and damage caused to the host if this thrips is released for biological control, it will contribute significantly to the management of Brazilian peppertree.

Varone L.,FuEDEI | Acosta M.M.,Instituto Nacional Of Medicina Tropical | Logarzo G.A.,FuEDEI | Briano J.A.,FuEDEI | And 2 more authors.
Florida Entomologist | Year: 2012

The cactus moth, Cactoblastis cactorum (Berg), is native to South America. Since its unintentional arrival to the United States in 1989 and to Mexican islands in 2006, it has become a serious threat to the diversity of both wild and cultivated species of Opuntia Mill, in North America. The native ecological host range of C. cactorum has not been directly ascertained and host acceptance is unclear. Taxonomic nomenclature of Opuntia spp. has been confusing, contradictory, and rapidly changing, leading to inaccurate conclusions about host plant use by C. cactorum in its native South American range. This study was conducted to better understand the biology and ecology of C. cactorum in Argentina by evaluating, under laboratory conditions, the insects' performance (survivorship, development time, potential fecundity) on 8 Opuntia spp. occurring in Argentina. Feeding trials were conducted on 5 Opuntia spp. native to Argentina and 3 Opuntia spp. native to Mexico. Cactoblastis cactorum larvae failed to feed on 2 native Opuntia spp., and had their greatest performance on the North American O. ficus-indica (L). Mill, and O. robusta H. L. Wendl. ex Pfeiff., and the South American O. arechavaletae Speg. Because the insects for the experiments were originally collected on O. ficus-indica, a reciprocal cross feeding experiment with insects collected on O. megapotamica Arechav. was also conducted to test for a potential host plant-mediated local adaptation effect. Some evidence for host plant adaptation was detected in populations collected on the South American host, O. megapotamica. Local adaptation, as documented here, could have consequences for the invasion process of C. cactorum in North America.

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