14 research outputs found
Plant bugs (Heteroptera: Miridae) associated with roadside habitats in Argentina and Paraguay: Host plant, temporal, and geographic range effects
Between November 1999 and September 2001, mirid nymphs (Hemiptera: Miridae) were collected on wild and cultivated plants in central and northern Argentina and southeastern Paraguay. In the laboratory, nymphs were reared until adult emergence. Four (Bryocorinae, Deraeocorinae, Mirinae, and Orthotylinae) of the eight mirid subfamilies were collected during the study. Twenty-two mirid species on 43 putative host plant species were collected in Argentina, and five species of mirids on eight plant species were collected in Paraguay. Eighty-five new mirid-plant associations were recorded (only 112 mirid-plant associations had been reported previously for Argentina). Most of the mirids were in the subfamily Mirinae, tribe Mirini, and most of the host plants belonged to Asteraceae. Almost all mirids were collected on plants with flower buds present. In addition to host plant records, the phenology and pattern of plant use for the most abundant mirids are reported. Mirid richness and abundance varied according to the host plant species; the highest diversity and richness of mirids occurred in the western region of Argentina (Salta, Jujuy, and Tucumán provinces). The most frequently collected mirid, Taylorilygus apicalis (Fieber) (≈87% of the 35,970 collected mirids), was usually collected on Asteraceae. This exotic species could have affected the native mirid fauna in the study area. More research on the possible interactions between T. apicalis and the native mirids of Argentina and Paraguay is needed. Our results suggest that T. apicalis exhibits regional polyphagy, i.e., uses numerous hosts throughout its geographic range.Facultad de Ciencias Naturales y Muse
Plant bugs (Heteroptera: Miridae) associated with roadside habitats in Argentina and Paraguay: Host plant, temporal, and geographic range effects
Between November 1999 and September 2001, mirid nymphs (Hemiptera: Miridae) were collected on wild and cultivated plants in central and northern Argentina and southeastern Paraguay. In the laboratory, nymphs were reared until adult emergence. Four (Bryocorinae, Deraeocorinae, Mirinae, and Orthotylinae) of the eight mirid subfamilies were collected during the study. Twenty-two mirid species on 43 putative host plant species were collected in Argentina, and five species of mirids on eight plant species were collected in Paraguay. Eighty-five new mirid-plant associations were recorded (only 112 mirid-plant associations had been reported previously for Argentina). Most of the mirids were in the subfamily Mirinae, tribe Mirini, and most of the host plants belonged to Asteraceae. Almost all mirids were collected on plants with flower buds present. In addition to host plant records, the phenology and pattern of plant use for the most abundant mirids are reported. Mirid richness and abundance varied according to the host plant species; the highest diversity and richness of mirids occurred in the western region of Argentina (Salta, Jujuy, and Tucumán provinces). The most frequently collected mirid, Taylorilygus apicalis (Fieber) (≈87% of the 35,970 collected mirids), was usually collected on Asteraceae. This exotic species could have affected the native mirid fauna in the study area. More research on the possible interactions between T. apicalis and the native mirids of Argentina and Paraguay is needed. Our results suggest that T. apicalis exhibits regional polyphagy, i.e., uses numerous hosts throughout its geographic range.Facultad de Ciencias Naturales y Muse
Plant bugs (Heteroptera: Miridae) associated with roadside habitats in Argentina and Paraguay: Host plant, temporal, and geographic range effects
Between November 1999 and September 2001, mirid nymphs (Hemiptera: Miridae) were collected on wild and cultivated plants in central and northern Argentina and southeastern Paraguay. In the laboratory, nymphs were reared until adult emergence. Four (Bryocorinae, Deraeocorinae, Mirinae, and Orthotylinae) of the eight mirid subfamilies were collected during the study. Twenty-two mirid species on 43 putative host plant species were collected in Argentina, and five species of mirids on eight plant species were collected in Paraguay. Eighty-five new mirid-plant associations were recorded (only 112 mirid-plant associations had been reported previously for Argentina). Most of the mirids were in the subfamily Mirinae, tribe Mirini, and most of the host plants belonged to Asteraceae. Almost all mirids were collected on plants with flower buds present. In addition to host plant records, the phenology and pattern of plant use for the most abundant mirids are reported. Mirid richness and abundance varied according to the host plant species; the highest diversity and richness of mirids occurred in the western region of Argentina (Salta, Jujuy, and Tucumán provinces). The most frequently collected mirid, Taylorilygus apicalis (Fieber) (≈87% of the 35,970 collected mirids), was usually collected on Asteraceae. This exotic species could have affected the native mirid fauna in the study area. More research on the possible interactions between T. apicalis and the native mirids of Argentina and Paraguay is needed. Our results suggest that T. apicalis exhibits regional polyphagy, i.e., uses numerous hosts throughout its geographic range.Facultad de Ciencias Naturales y Muse
Electrophysiological and behavioral characterization of bioactive compounds of the Thymus vulgaris, Cymbopogon winterianus, Cuminum cyminum and Cinnamomum zeylanicum essential oils against Anopheles gambiae and prospects for their use as bednet treatments
Recommended from our members
Management of Pyrethoid-Resistant Whiteflies in Arizona Cotton: Selection, Cross-Resistance, and Dynamics
In 1995, silverleaf whitefly, Bemisia argentifolii Bellows and Perring, resistance to the widely -used mixture of Danitol® (fenpropathrin) + Orthene® (acephate) was shown to be severe and widespread in Central Arizona cotton. Thereafter, laboratory experiments were undertaken to identify the other major insecticides that were affected by this resistance. Whiteflies were collected in November of 1995 from Maricopa (highly resistant) and Yuma (relatively susceptible) County locations in Arizona. A composite colony was established by combining Yuma and Maricopa whiteflies in a 4:1 ratio. After six generations of adult selection of this population with Danitol + Orthene, appreciable shifts in the concentration responses for pyrethroid, organophosphate, and carbamate insecticides were observed, indicating heritable variation for resistance in the source populations. From this we obtained definitive proof that resistance to Danitol + Orthene confers cross-resistance to Asana® (esfenvalerate), Capture® (bifenthrin), Danitol, Decis® (deltamethrin), Decis + Orthene, and Karate® (lambda-cyhalothrin). Additionally, selection with Danitol + Orthene resulted in statistically significant reductions in susceptibility to Curacron® (profenofos), Lannate® (methomyl), Monitor® (methamidaphos), and Ovasyn® (amitraz). Studies were performed to assess tolerance of Maricopa (pyrethroid- resistant) and Yuma (pyrethroid-susceptible) populations to a diversity of conventional insecticides currently registered for use in Arizona cotton, with the intention of finding compounds that showed promise for overcoming pyrethroid resistance. Of the materials evaluated, Curacron, Lannate, Lorsban® (chlorpyrifos), Ovasyn, Supracide® (methidathion), and Vydate® (oxamyl) were most promising. To determine to what degree pyrethroid resistance in cotton influenced resistance in winter vegetables and melons, and vice versa, whitefly populations were collected from a succession of these crops in Western and Central Arizona regions. In most instances, the whiteflies in Western Arizona were significantly more susceptible to Danitol + Orthene than those in Central Arizona. Significant decreases were found in susceptibility to Danitol + Orthene during the 1996 season at three of the four locations in which multiple crops were monitored. This emphasizes that pyrethroid resistance levels can be increased in whitefly populations from any of the cotton, melons, or other winter vegetable crops evaluated. Therefore, management of pyrethroid resistance in Arizona cotton will require harmonizing resistance management efforts and specifically limiting pyrethroid use in the entire crop complex
Recommended from our members
Defining the Risk of Resistance to Imidacloprid in Arizona Whitefly
A resistance management program for imidacloprid was initiated in Arizona in 1995, the ultimate goal of which is to sustain the efficacy of this insecticide against Bemisia. The current paper reviews our progress toward defining the risk of resistance to imidacloprid in Arizona whiteflies. Bioassay methods for adult whitefly consisted of a 1 day hydroponic uptake by cotton seedlings, followed by a 2 day exposure period. Results from statewide monitoring indicate that whitefly populations throughout Arizona are susceptible to imidacloprid; however, slight increases in resistant whiteflies were observed in 1996, as compared to 1995. Thus far, selection studies with various Arizona whitefly populations have not led to reduced susceptibility to imidacloprid. In a study exploring the influences of different cropping systems on imidacloprid use, we found no major differences in susceptibility to imidacloprid between populations of whiteflies in central and southwestern Arizona. Continued effective management of Arizona whitefly will, in part, hinge on our ability to more effectively integrate our knowledge of whitefly biology with resistance management strategies
Recommended from our members
Can Resistance to Chloronicotynl Insecticides be Averted in Arizona Field Crops?
A resistance management program was initiated in Arizona in 1995, the initial goal of which was to sustain the efficacy of imidacloprid (Admire®) against Bemisia in vegetable crops. Due to the anticipated registration of additional chloronicotinyl (and related neonicotinyl) insecticides in Arizona, project objectives were subsequently broadened to address management of this entire class of insecticides in Arizona field crops. Results from three years of statewide monitoring of whiteflies from cotton indicated that whitefly populations in Arizona have become significantly less susceptible to imidacloprid in each of the past two years and significant geographical differences were described. However, no evidence was found of reduced field performance of imidacloprid in vegetables. Additionally, laboratory studies subjecting Arizona whiteflies to selection with imidacloprid did not increase levels of resistance beyond those occurring in the field. A study exploring the influence of cropping system differences on imidacloprid use (Admire® and Provado®) revealed no major differences in susceptibility to this insecticide between populations of whiteflies in central and southwestern Arizona. However, distinct seasonal shifts to lower susceptibility from 1996 to 1997 were observed in the Dome Valley of southwestern Arizona. Susceptibility of Arizona whitefly populations to imidacloprid was highly correlated with susceptibility to acetamiprid but was unrelated to susceptibility to CGA-293343. There is an urgent need to harmonize chemical use and resistance management efforts in Arizona cotton, vegetables and melons to avoid conflicts resulting from movement of pests between crops
Recommended from our members
Whitefly Control in Arizona Vegetables: Development of a Resistance Management Program for Imidacloprid (Admire®)
In 1995 we initiated a resistance management program aimed at sustaining the efficacy of Admire®. This paper delineates the groundwork for the program, and describes methodological and conceptual advances toward our goal. Bioassay methods developed for adult whitefly consisted of a 1 day hydroponic uptake procedure using cotton seedlings. A reliable mortality criterion was also established. Results from a statewide survey suggested slight geographic variation in whitefly susceptibility to Admire®. Future studies will 1) continue to monitor susceptibility throughout Arizona, 2) evaluate the risk of resistance to whitefly populations in commercial greenhouses, and relate this to field populations, and 3) characterize the development of resistance in relation to cropping systems and spatial dynamics of whitefly. The overall objective of these investigations is to determine if a sustainable use strategy can be identified for Admire®