Progress 09/15/06 to 08/31/09
Outputs
OUTPUTS: Field and laboratory experiments have shown excellent promise in the use of reduced risk and biological pesticides to control the citrus leaf miner (CLM) (Phyllocnistis citrella), and the Asian citrus butterfly (Papilio demoleus). The latter is an invasive pest expected to have moderate economic impact on the citrus industry, especially on new plantings. Laboratory experiments with third instar larvae showed that excellent control could be achieved with the use of the biological pesticide Bacillus thuringiensis subs. kurstaki, and of the reduced risk pesticide spinosad, as compared with the control. Other pesticides such as, azadirachtin and rosemary oil were not better controlling the pest than the control (surfactant alone). We also determined and published relevant life history parameters for this papilionid butterfly. Finally we reported the generalist predator Zelus longipes (Homoptera: Reduviidae) as an important source of larval mortality. Our research also provides information to producers on effective biological and reduced-risk alternatives to CLM control. Field-testing of six biological and reduced risk pesticides in two Tahiti lemon nurseries have demonstrated that some of them are effective against the CLM, even under high pest population pressures. We applied pesticides using CO2-powered sprayers at 100 psi; each product was sprayed in conjunction with an organo-silicate surfactant. We applied sham control plants with surfactant at the same spray pressure. We found that spinosad, azadirachtin, and abamectin are capable of suppressing CLM well below economic injury levels (one larva per leaf per growing tip). Other pesticides tested [i.e., B. t. subsp azawai, B.t. subsp. kurstaki, and Ecotrol (Rosemary oil)] did not perform better than the controls. In limited samplings collected from both nurseries sampled, Pnigalio sp. was the most common parasitoid found attacking CLM. Another finding was the confirmation of anecdotal observations that characterize CLM attack intensity higher at lower elevation. CLM attack to nursery stock at Lajas AES (100 ft elev.) was 4-5 times greater than that observed at Adjuntas AES (2,500 ft. elev.). One factor that may explain this finding is the much higher levels of parasitism of Pnigalio sp. at Adjuntas (73.3% n=60 larvae) than at Lajas (6.7% n=60 larvae). A survey of coccinellid predators in over ninety sites in the citrus growing municipalities in western and central Puerto Rico was conducted Several species are commonly collected including: Coelophora inaequalis, Chilocorus cacti, Psorolyma maxillosa, Coleomegilla innotata, Cycloneda sanguinea, Olla v-nigrum, Procula ferruginea, Cryptolaemus montrouzieri, Decadiumus pictus, Decadioumus sp., Pentilia discors, Zilus gilvifrons, Z. variipenis, Delphastus nebulosus, and Stethorus caribus; Diomus ochroderus, and D. roseicollis. Preparation of pest prey profiles and immature identifications are under way. Based on this effort a review of ladybeetles of Puerto Rico is in preparation, and also the writing of an educational book for schools and general public. PARTICIPANTS: Alex Segarra (PI) and Fernando Gallardo (Co-PI) Department of Crops and Agroenvironmental Sciences TARGET AUDIENCES: Extension Agents Extension Specialists Citrus Producers Citrus Researchers General Public PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Results from this research will help demonstrate, to producers in Puerto Rico, the feasibility of using biologically-based and reduced risk pesticides to manage key insect pests of citrus nurseries and of new citrus plantings. In addition, producers can now fully appreciate the importance of natural enemy conservation through the use of reduced risk pesticides. In some cases, the use of our results by producers may allow an easier transition into organic production, and in other cases could lead them to use pest control alternatives that are both safer to the applicator and gentler on the environment. In addition, a survey and assessment of common natural enemies will allow further work to be carried out on the effects of management practices on their populations. Finally, information gathered under this project has advanced our knowledge of the Asian citrus butterfly life cycle and reproduction.
Publications
- Segarra-Carmona, A.E., L. E. Flores-Lopez, and L. Morales-Collado. 2008. Ciclo de vida y control de la mariposa asiatica de los citricos, Papilio demoleus (Lepidoptera: Papilionidae), una nueva plaga invasiva en Puerto Rico. (Life cycle and control of the Asian citrus butterfly, Papilio demoleus (Lepidoptera: Papilionidae). In Press, Journal of Agriculture of the University of Puerto Rico.
- Segarra Carmona, A.E. 2010. The Coccinellidae of Puerto Rico: A review. J. Agric. UPR. In preparation for submission.
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Progress 09/15/07 to 09/14/08
Outputs
OUTPUTS: Field and laboratory experiments have shown excellent promise in the use of reduced risk and biological pesticides to control the citrus leaf miner (CLM) (Phyllocnistis citrella) and the Asian citrus butterfly (Papilio demoleus). The latter is an invasive pest and it is expected to have moderate economic impact on the citrus industry, especially on new plantings. Laboratory experiments with third instar larvae showed that excellent control could be achieved with the use of the biological pesticide Bacillus thuringiensis subs. kurstaki, and with use of the reduced risk pesticide spinosad, as compared with the control. Other pesticides, such as azadirachtin and rosemary oil, were no better at controlling the pest than the control surfactant alone. We also determined and published relevant life history parameters for this papilionid butterfly. Finally we report the generalist predator Zelus longipes (Homoptera: Reduviidae) as an important cause of larval mortality. Our research also provides information to producers on effective biological and reduced-risk alternatives to CLM control. Field-testing of six biological and reduced-risk pesticides in two Tahiti lemon nurseries has demonstrated that some are effective against the CLM, even under high pest population pressures. We applied pesticides by using CO2-powered sprayers @ 100 psi, each product sprayed in conjunction with an organo-silicate surfactant. We applied sham control plants with surfactant at the same spray pressure. We found that spinosad, azadirachtin, and abamectin are capable of suppressing CLM well below economic injury levels (one larva per leaf per growing tip) as compared to the control. Other pesticides tested (i.e., B. t. subsp azawai, B.t. subsp. kurstaki, and Ecotrol (Rosemary oil) did not perform better than controls. Pnigalio sp., was the most common parasitoid found attacking CLM, in limited samplings collected from both nurseries sampled. Another finding was the confirmation of anecdotal observations that characterize CLM attack intensity higher at lower elevations. CLM attack on nursery stock at Lajas AES (100-ft elev.) was four to five times greater than that observed at Adjuntas AES (2,500 ft. elev.). One factor that may explain this finding is the much higher levels of parasitism of Pnigalio sp. at Adjuntas (73.3% n=60 larvae) than at Lajas (6.7% n=60 larvae). Survey of coccinellid predators has been underway for the past nine months. Over 90 sites have been used for collection in the citrus-growing municipalities of western and central Puerto Rico. Several species commonly collected include Coelophora inaequalis, Chilocorus cacti, Psorolyma maxillosa, Coleomegilla innotata, Cycloneda sanguinea, Olla v-nigrum, Procula ferruginea, Cryptolaemus montrouzieri, Decadiumus pictus, Decadioumus sp., Pentilia discors, Zilus gilvifrons, Z. variipenis, Delphastus nebulosus, and Stethorus sp., Scymnus thoracicus, and S. roseicollis. Preparation of pest prey profiles and immature identifications are underway. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Results from this research will demonstrate to producers in Puerto Rico the feasibility of using biologically-based and reduced-risk pesticides to manage key insect pests of citrus nurseries and of new citrus plantings. In some cases, the use of our results by producers may allow an easier transition into organic production, and in other cases could lead them to use pest control alternatives that are both safer to the applicator and gentler on the environment. In addition, a survey and assessment of common natural enemies is underway, investigation which will allow further work to be carried out on population management practices. Finally, information gathered under this project has advanced our knowledge of the Asian citrus butterfly life cycle and reproduction.
Publications
- Segarra-Carmona, A.E., L. E. Flores-Lopez, and L. Morales-Collado. 2008. Ciclo de vida y control de la mariposa asiatica de los citricos, Papilio demoleus (Lepidoptera: Papilionidae), una nueva plaga invasiva en Puerto Rico. [Life cycle and control of the Asian citrus butterfly, Papilio demoleus (Lepidoptera: Papilionidae)]. In Press, Journal of Agriculture of the University of Puerto Rico.
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Progress 09/15/06 to 09/14/07
Outputs
Our field and laboratory experiments show excellent promise in the use of reduced risk and biological pesticides to control the citrus leaf miner (CLM) (Phyllocnistis citrella) and the Asian citrus butterfly (Papilio demoleus). The latter is an invasive pest recently reported from Puerto Rico in 2006, and it is expected to have moderate economic impact on the citrus industry, especially on new plantings. Our laboratory experiments with third instar larvae showed that excellent control of the Asian citrus butterfly could be achieved with the use of the biological pesticide Bacillus thuringiensis subs. kurstaki, and of the reduced risk pesticide spinosad, as compared with the control. Other pesticides such as azadirachtin and rosemary oil were no better controlling the pest than the control (surfactant alone). We also determined relevant life history parameters for this papilionid butterfly, finding that development from egg to adult takes about thirty days (shorter in
males). In addition, head capsule measurements are now available for each instar and stadia. Finally, we report the generalist predator Zelus longipes (Homoptera: Reduviidae) as an important source for larval mortality. Further work is now concentrated in determining sub-lethal effects of pesticides on the butterfly. Our research also provides information to producers on effective biological reduced-risk alternatives to CLM control. Field testing of six biological reduced risk pesticides in two Tahiti lemon nurseries has demonstrated that many are effective against the CLM, even under high pest population pressures. We applied pesticides using CO2-powered sprayers @ 100 psi, each product sprayed in conjunction with an organo-silicate surfactant. We applied sham control plants with surfactant at the same spray pressure. We found that spinosad, azadirachtin and abamectin are capable of suppressing CLM well below economic injury levels (one larva per leaf per growing tip) as compared to
those of the control. Other pesticides tested [i.e., B. t. subsp azawai, B.t. subsp. kurstaki, and Ecotrol-registered trademark (Rosemary oil)] did not perform better than the controls. Pnigalio sp was the most common parasitoid found attacking CLM in limited samplings collected from both nurseries sampled. Another finding was the confirmation of anecdotal observations that characterize CLM attack intensity higher at lower elevation. CLM attack on nursery stock at Lajas AES (100 ft elev.) was four to five times greater than that observed at Adjuntas AES (2,500 ft. elev.). One factor that may explain this finding is the much higher levels of parasitism of Pnigalio sp. at Adjuntas (73.3% n=60 larvae) than at Lajas (6.7% n=60 larvae). Further pesticide work is now being conducted at the young planting stage (< 1 year seedlings), and to document effects on other pests common in drier cooler months [e.g., citrus aphids (Toxoptera spp.), spirea aphids (Aphis spiraecola), citrus psyllids
(Diaphorina citri), and broad mites (Poligophagotarsonemus latus)].
Impacts
Results from this research will demonstrate to producers in Puerto Rico the feasibility of using biologically-based reduced risk pesticides to manage key insect pests of citrus nurseries and of new citrus plantings. In some cases, the application of our results may allow some producers to more easily transition into organic production, and in other cases could lead them to use pest control alternatives that are both safer to the applicator and gentler on the environment. Finally, information gathered under this project has advanced our knowledge of the Asian citrus butterfly life cycle and reproduction.
Publications
- Segarra-Carmona, A. E., L. E. Flores-Lopez, and L. Morales-Collado. 2008. Ciclo de vida y control de la mariposa asiatica de los citricos, Papilio demoleus (Lepidoptera: Papilionidae), una nueva plaga invasiva en Puerto Rico. [Life cycle and control of the Asian citrus butterfly, Papilio demoleus (Lepidoptera: Papilionidae), A new invasive pest in Puerto Rico. Submitted to the Journal of Agriculture of the University of Puerto Rico' Editorial Board].
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