Biology of Anthonomus testaceosquamosus Linell, 1897 (Coleoptera: Curculionidae): A New Pest of Tropical Hibiscus.

Originating in northeastern Mexico and southern Texas, the hibiscus bud weevil (HBW), Anthonomus testaceosquamosus Linell 1897, was discovered infesting China rose hibiscus (Hibiscus rosa-sinensis L.) in south Florida in May 2017. Although the biologies of the congeneric boll weevil, A. grandis Boheman 1843, and pepper weevil, A. eugenii Cano 1894 are well documented, no data are available regarding the biology of HBW. Here, we present a comprehensive study on the biology of this pest when reared at 10, 15, 27 and 34 °C and on different food sources. This weevil has three larval instars and its life cycle was completed only at 27 ± 1 °C. Weevil development was similar on an artificial diet when compared with a diet of hibiscus buds. Adult HBW could survive solely on pollen, but reproduction did not occur. Without water, HBW survived for ≈15 days; survival times reached nearly 30 days when water was accessible. Our results suggest that if left unmanaged, HBW has the potential to cause significant economic damage to the hibiscus industry. Given that a comprehensive understanding of a pest's biology is critical for development of effective integrated pest management, our results provide a foundation for future research endeavors to mitigate the impact of this weevil in south Florida.

An Ecological Assessment of Isaria fumosorosea Applications Compared to a Neonicotinoid Treatment for Regulating Invasive Ficus Whitefly.

A pilot study was conducted on a weeping fig, Ficus benjamina shrub hedge in a Florida urban landscape to determine the efficacy of a fungal biopesticide, PFR-97™ which contains blastospores of Isaria fumosorosea, and a neonicotinoid treatment (Admire Pro™) applied against the invasive ficus whitefly pest, Singhiella simplex (Singh). Post treatment, an ecological assessment of the study was conducted by observing the impact of the fungal biopesticide and neonicotinoid treatment on natural enemies, e.g., predators, parasitoids and enzootic fungal pathogens occurring in the whitefly-infested hedge. Both treatments provided a significant reduction in the whitefly population compared to control and were compatible with the natural enemies present. Various natural enemies including fungal entomopathogens were identified associated with the whitefly population infesting the weeping fig hedge. The parasitoids, Encarsia protransvena Viggiani and Amitus bennetti Viggiani & Evans combined parasitized a similar mean number of whitefly nymphs in both treatments and control; however, the number parasitized decreased over time. Natural enzootic fungi isolated from the ficus whitefly nymphs were I. fumosorosea, Purpureocillium lilacinum and Lecanicillium, Aspergillus and Fusarium species. Results from this pilot study suggest there is much potential for using repeated applications of the fungal biopesticide, PFR-97™ as a foliar spray compared to a neonicitionid as a soil drench for managing S. simplex on Ficus species for ≥28 days.

Population dynamics of Scirtothrips dorsalis (Thysanoptera: Thripidae) and other thrips species on two ornamental host plant species in Southern Florida.

Since its 2005 introduction into the United States, chilli thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae), has become a problematic pest of agronomic, vegetable, fruit, and ornamental plants. Knowledge of its population dynamics may help managers better monitor and control S. dorsalis. Population estimates were recorded for S. dorsalis and other thrips species on Knock-Out rose (Rosa 'Radrazz') and green buttonwood (Conocarpus erectus L.) from July 2007 to September 2008 in two field plots (one per plant species) in Homestead, FL. Yellow sticky card traps and samples of terminals, flowers, buds, and leaves were collected. S. dorsalis accounted for 95% of all thrips individuals collected from plants and 84% from traps with the remainder including at least 18 other thrips species. More thrips were caught on or flying near rose plants (47,438) than on or near buttonwoods (5,898), and on-plant densities of S. dorsalis appeared higher for rose than for buttonwood. Compared with rose leaves, rose buds, terminals, and flowers each had higher numbers of S. dorsalis, and buds and terminals had higher densities. On each host plant species, S. dorsalis density fluctuated over time with peaks in the late spring, summer, and fall, but populations were consistently low in the late winter and early spring. On roses, increased plant damage ratings correlated with reduced numbers of flowers and buds, reduced mean flower areas, and increased on-plant number and density of S. dorsalis. There were positive correlations over time between S. dorsalis density and plant damage rating for rose flowers (R = 0.78; P = 0.0003) and for buttonwood terminals (R = 0.90; P = 0.0001). Yellow sticky card traps were effective for monitoring S. dorsalis and may be especially useful and economically justified for the most susceptible hosts, but they also work well for less susceptible hosts. A good S. dorsalis scouting program should hence consider trap catches and symptoms such as leaf distortion, small flower area (size), and thrips population concentrations near buds and terminals.

Developmental time, longevity, and lifetime fertility of three introduced parasitoids of the mealybug Paracoccus marginatus (Hemiptera: Pseudococcidae).

Developmental time, longevity, and lifetime fertility of three previously introduced parasitoids (Acerophagus papayae Noyes and Schauff, Anagyrus loecki Noyes and Menezes, and Pseudleptomastix mexicana Noyes and Schauff) (Hymenoptera: Encyrtidae) of the mealybug Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) were studied in the laboratory to understand the outcome of their recovery in field studies conducted in the United States. The developmental time of both male and female A. papayae and A. loecki was shorter than the developmental time of male and female P. mexicana. Male parasitoids of all three species had a shorter developmental time than their females. All parasitoids had a shorter developmental time in adult-female mealybugs than in second instars. Mating status (unmated and mated) had no effect on the male longevity. Unmated and mated females that were not allowed to oviposit had similar longevity and lived longer than those that were allowed to oviposit. Virgin females produced male only progeny with higher number of males from A. loecki or P. mexicana than from A. papayae. The number of females and the cumulative progeny was smaller for A. papayae than for A. loecki or P. mexicana. The progeny sex ratio (proportion of females) was not different among the parasitoids. A. papayae had the shortest reproductive period followed by A. loecki and P. mexicana, respectively. This information is important in evaluating the efficiency, recovery and establishment of A. papayae, A. loecki, and P. mexicana.

Host instar susceptibility and selection and interspecific competition of three introduced parasitoids of the mealybug Paracoccus marginatus (Hemiptera: Pseudococcidae).

Three previously introduced parasitoids (Acerophagus papayae Noyes and Schauff, Anagyrus loecki Noyes and Menezes, and Pseudleptomastix mexicana Noyes and Schauff [Hymenoptera: Encyrtidae]) of the mealybug Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae) were studied for their host instar susceptibility and sex ratio, host instar selection, and interspecific competition in the laboratory. All three parasitoids were able to develop in the second instars, third-instar females, and adult females of P. marginatus. No progeny emerged from first-instar mealybugs. The proportion of female emergence was increased with increasing host size. Parasitoids selected their host instars for oviposition when they had a choice. Between second- and third-instar hosts, A. papayae and P. mexicana had significantly higher parasitism in second-instar mealybugs, whereas A. loecki had higher parasitism in the third-instar mealybugs. When competed with either one or two parasitoid species, A. papayae was significantly more successful in second-instar hosts and A. loecki was significantly more successful in third-instar mealybugs. P. mexicana was significantly less competitive when with A. papayae in both second and third instars, with A. loecki in third instars and with both A. papayae and A. loecki in second and third instars. Overall, A. papayae provided a better control of the host, when present singly or with the other two parasitoids. This information is important in evaluating the efficiency of A. papayae, A. loecki, and P. mexicana and understanding the outcome of their recovery and establishment in field studies conducted in Florida.

Life history of Paracoccus marginatus (Hemiptera: Pseudococcidae) on four host plant species under laboratory conditions.

Life history of the mealybug, Paracoccus marginatus Williams and Granara de Willink, on three ornamental plants [Hibiscus rosa-sinensis L., Acalypha wilkesiana (Muell.-Arg.), and Plumeria rubra L.] and one weed species (Parthenium hysterophorus L.) was studied under laboratory conditions. Mealybugs were able to develop, survive, and reproduce on all four hosts; however, there were differences in the life history parameters. Adult females that developed on acalypha and parthenium emerged approximately 1 d earlier than those that developed on hibiscus and plumeria. Adult males had a longer developmental time on plumeria than on the other hosts. Survival of first- and second-instar nymphs and cumulative adult survival were lowest on plumeria. Longevity was not affected by hosts for males and females and averaged 2.3 +/- 0.1 and 21.2 +/- 0.1 d, respectively. On plumeria, 58.9 +/- 1.7% of the adults were females, which was a higher female percentage than on the other hosts. No egg production occurred in virgin females. Prereproductive and reproductive periods of the females were not affected by hosts and averaged 6.3 +/- 0.1 and 11.2 +/- 0.1 d, respectively. Mean fecundity of 186.3 +/- 1.8 eggs on plumeria was lower than on the other three plant species. Life history parameters of P. marginatus on hibiscus, acalypha, plumeria, and parthenium show its ability to develop, survive, and reproduce on a wide variety of plant species.

Life history of the mealybug, Maconellicoccus hirsutus (Hemiptera: Pseudococcidae), at constant temperatures.

Important life history parameters of the mealybug, Maconellicoccus hirsutus (Green), were characterized on hibiscus (Hibiscus rosa-sinensis L.) cuttings at six constant temperatures between 15 and 35 degrees C. The development of M. hirsutus was the fastest at 27 degrees C, where the mealybugs completed development in approximately 29 d. The lower (T(min)) and upper (T(max)) developmental thresholds and the optimal developmental temperature (T(opt)) for the development of female mealybugs were estimated as 14.5, 35, and 29 degrees C, respectively. The thermal constant (K), which is the number of temperature-day or degree-day units required for development, of the females was 347 DD. The original distribution range prediction (based on T(min) = 17.5 degrees C and K = 300 DD) indicated that M. hirsutus could complete at least one generation in all of the continental United States. However, results of this study suggested that the distribution range of M. hirsutus may expand northward because of the lower T(min), and the predicted number of generations in a year may be lower because of the higher K required to complete each generation. The average cumulative survival rate of M. hirsutus at 25 and 27 degrees C was 72%, which was significantly higher than 51 and 62% at 20 and 30 degrees C, respectively. M. hirsutus reproduced sexually, with each mated female producing 260-300 eggs between 20 and 27 degrees C but only approximately 100 eggs at 30 degrees C. Female longevity was reduced from 28 d at 20 degrees C to 19-21 d at 25-30 degrees C. At 27 degrees C, the net reproductive rate (R(o)) was estimated at 165 female symbol/female symbol, the intrinsic rate of population increase (r(m)) was 0.119 (female symbol/female symbol/d), the generation time (T(G)) was 43 d, and the doubling time (DT) was 5.8 d. The life table statistics suggested that the currently released biological control agents, which have higher r(m) than M. hirsutus, will be able to complete more generations than the mealybug within the tested temperature range; thus, they are effective against M. hirsutus.

Effect of temperature on the life history of the mealybug Paracoccus marginatus (Hemiptera: Pseudococcidae).

Effect of temperature on the life history of the mealybug Paracoccus marginatus Williams & Granara de Willink (Hemiptera: Pseudococcidae) was investigated in the laboratory. P. marginatus was able to develop and complete its life cycle at 18, 20, 25, and 30 +/- 1 degrees C. At 15, 34, and 35 degrees C, the eggs hatched after 27.5, 5.9, and 5.5 d of incubation, respectively, but further development of the first-instar nymphs was arrested. No eggs hatched at 37 degrees C. The developmental time for egg to adult was the longest at 18 degrees C for both males and females. Approximately 80-90% of the eggs survived between 20 and 30 degrees C. The highest fecundity was at 25 degrees C with each female producing an average of 300 eggs. Adult longevity, and preoviposition and oviposition periods increased with decreasing temperature up to 25 degrees C. The proportion of females was approximately 42% at 25 degrees C and was between 70 and 80% at 18, 20, and 30 degrees C. Adult males and females required 303.0 and 294.1 degree-days (DD), respectively, to complete their development. The estimated minimum temperature thresholds for the adult males and females were 14.5 and 13.9 degrees C, respectively. For adult males, the estimated optimum and maximum temperature thresholds were 28.7 and 31.9 degrees C; and for adult females, they were 28.4 and 32.1 degrees C, respectively. The ability of P. marginatus to develop, survive, and reproduce successfully between 18 and 30 degrees C suggests that it has the capability to develop and establish in areas within this temperature range.

Chlorpyrifos immersion to eliminate third instars of Japanese beetle (Coleoptera: Scarabaeidae) in balled and burlapped trees and subsequent treatment effects on red maple.

This study examined chlorpyrifos immersion of balled and burlapped (B&B) nursery trees for elimination of third instars of Japanese beetle, Popillia japonica Newman (Coleoptera: Scarabaeidae), and for phytotoxicity on red maple, Acer rubrum L. Trees were harvested as 45- and 60-cm-diameter B&B and immersed in chlorpyrifos at U.S. Domestic Japanese Beetle Harmonization Plan rate (0.24 kg active ingredient [AI/100 liters) or lower rates of 0.015, 0.03, 0.06, and 0.12 kg (AI)/100 liters. The 0.03, 0.06, and 0.24 kg (AI) rates provided 100% control of Japanese beetle grubs in both 45- and 60-cm B&B. The 0.015 and 0.12 kg (AI) chlorpyrifos rates were 100% effective in three tests. However, in another test, 0.015 and 0.12 kg (AI) chlorpyrifos treatments had four (93% control) and one (98% control) grubs recovered, respectively. Root ball soils consisted of loam, silt loam, or clay loam texture classifications. Trunk diameter and internode growth of red maple harvested as 45-cm B&B decreased linearly with increasing chlorpyrifos dip rate during the first year, but effects were unapparent in the second year. Chlorpyrifos rates had no measurable impact on growth of red maples harvested as 60-cm B&B. No visual phytotoxicity symptoms were detected for chlorpyrifos rate or root ball size treatments. In conclusion, results support lowering the U.S. Domestic Japanese Beetle Harmonization Plan chlorpyrifos dip rate for category 2 states to at least 0.03 kg (AI) for B&B diameters < or =60 cm. Chlorpyrifos rates < 0.24 kg (AI) will lower cost, reduce worker exposure, and lessen potential environmental contamination.

Survival of adult Tiphia vernalis (Hymenoptera: Tiphiidae) after insecticide, fungicide, and herbicide exposure in laboratory bioassays.

Tiphia vernalis Rohwer is a hymenopteran ectoparasitoid of Japanese beetle, Popillia japonica Newman, larvae. The adult wasps feed on nectar or honeydew between mid-April and late June. Adults may contact pesticides when landing on foliage or when females hunt for grubs in the soil. The lethal effect of nursery, turf, and landscape pesticides was determined by exposing wasps to treated foliage in the laboratory. Pesticides tested at labeled rates were the insecticides bifenthrin, carbaryl, chlorpyrifos, halofenozide, and imidacloprid; the herbicides oryzalin, pendimethalin, and a combination product with 2,4-D, dicamba, and mecoprop (multiherbicide); and the fungicides chlorothalonil and thiophanate-methyl. During 2001 and 2002, male and female T. vernalis were exposed to pesticides by using turf cores. For both years, bifenthrin, chlorpyrifos, and imidacloprid treatments lowered adult survival relative to the control, but halofenozide had minimal effect on mortality of males and females. More males than females died after exposure to carbaryl treatments. Survival of females was not reduced by exposure to herbicides or fungicides. Females were apparently more tolerant of pesticides than males. Mortality of males in response to herbicides and fungicides was more variable than for females; in 2002 trials, male mortality was higher after exposure to multiherbicide, oryzalin, pendimethalin, and thiophanate-methyl than the control. The fungicide chlorothalonil did not increase mortality of males or females in either year. Sublethal effects were not evaluated. The study indicates the choice of pesticide may be important for conserving T. vernalis in nursery, landscape, and turf settings.

Effect of insecticides on Tiphia vernalis (Hymenoptera: Tiphiidae) oviposition and survival of progeny to cocoon stage when parasitizing Popillia japonica (Coleoptera: Scarabaeidae) larvae.

The effect of insecticides on oviposition of Tiphia vernalis Rohwer and subsequent survival of parasitoid progeny to the cocoon stage was determined in the laboratory by using larval Japanese beetle, Popillia japonica Newman, as the host. Insecticides tested were imidacloprid, thiamethoxam, halofenozide, chlorpyrifos, and carbaryl at labeled rates. Female T. vernalis were allowed 2 d to parasitize P. japonica larvae after the parasitoids had received a 4-d exposure to insecticide-treated soil. Another group of female T. vernalis were allowed 2 d to parasitize P. japonica larvae that had been exposed to insecticide-treated soil for 3-4 d. Percentage of parasitism of P. japonica larvae in these trials after exposure of adult parasitoids to carbaryl, chlorpyrifos, halofenozide, or imidacloprid-treated soil (23.3-50.0%) or adult parasitoids to chlorpyrifos, halofenozide, or imidacloprid-treated grubs (33.0-56.7%) was not negatively affected relative to the control treatment (21.7-54.2%). A third group of adult T. vernalis and P. japonica larvae were simultaneously exposed to chlorpyrifos or carbaryl treatments. Percentage parasitism in these trials was lower for T. vernalis adults exposed to the chlorpyrifos and carbaryl (15.0-25.0%) relative to the control (57.5-62.5%) with the exception of one trial with carbaryl (40.0%). However, exposure of the parasitoid and P. japonica to chlorpyrifos 0.5X, carbaryl 0.5X, imidacloprid, halofenozide, or thiamethoxam in several trials resulted in parasitism that was equivalent or greater than (45.0-80.0%) the untreated control (57.5-62.5%). Japanese beetle larval mortality in these trials was greater in the insecticide and parasitoid combination (97.5-100.0%) than with insecticides alone (45.0-100.0%). Percentage of survival of T. vernalis progeny to the cocoon stage was not negatively affected by a 4-d adult parasitoid exposure to carbaryl and chlorpyrifos treated soil (11.7-16.7% versus 18.3% control) or a 2-d exposure to P. japonica-treated larvae (16.7-18.3% versus 28.3% control). However, simultaneous exposure of T. vernalis progeny and P. japonica larvae to chlorpyrifos- and carbaryl-treated soil resulted in no parasitoids surviving to the cocoon stage. Between neonicotinoids, thiamethoxam had more adverse impact on percentage parasitism (52.5%) and survival to the cocoon stage (10.0%) than imidacloprid (80.0 and 32.5%, respectively). Results of this study indicate soil incorporation of imidacloprid and halofenozide had minimal effect on the number of P. japonica larvae parasitized by T. vernalis or survival of T. vernalis progeny to the cocoon stage; therefore, they are more suitable for use with T. vernalis. In contrast, chlorpyrifos, carbaryl, and thiamethoxam lowered the number of T. vernalis progeny surviving to the cocoon stage, and carbaryl and chlorpyrifos reduced the number of P. japonica larvae parasitized. The soil incorporation of insecticides is discussed as one explanation for the minimal effects of some insecticides on T. vernalis.