Van Driesche Research Articles

Effect of Afidopyropen against Myzus persicae (Hemiptera: Aphididae) and Its Predator, Adalia bipunctata (L.) in a Greenhouse

Effect of Afidopyropen against Myzus persicae (Hemiptera: Aphididae) and Its Predator, Adalia bipunctata (L.) in a Greenhouse

Increased Calcium Influx through L-type Calcium Channels in Human and Mouse Neural Progenitors Lacking Fragile X Mental Retardation Protein.

SummaryThe absence of FMR1 protein (FMRP) causes fragile X syndrome (FXS) and disturbed FMRP function is implicated in several forms of human psychopathology. We show that intracellular calcium responses to depolarization are augmented in neural progenitors derived from human induced pluripotent stem cells and mouse brain with FXS. Increased calcium influx via nifedipine-sensitive voltage-gated calcium (Cav) channels contributes to the exaggerated responses to depolarization and type 1 metabotropic glutamate receptor activation. The ratio of L-type/T-type Cav channel expression is increased in FXS progenitors and correlates with enhanced progenitor differentiation to glutamate-responsive cells. Genetic reduction of brain-derived neurotrophic factor in FXS mouse progenitors diminishes the expression of Cav channels and activity-dependent responses, which are associated with increased phosphorylation of the phospholipase C-γ1 site within TrkB receptors and changes of differentiating progenitor subpopulations. Our results show developmental effects of increased calcium influx via L-type Cav channels in FXS neural progenitors.

Irreplaceable Mortality: Is It?

Peterson et al. (2009) presented an analysis of mortality rates of herbivorous insects using published life tables. For each mortality factor in each life table, they estimated the marginal attack rate (hereinafter, “marginal mortality rate”), i.e., the mortality rate expected in the absence of contemporaneous mortality factors assuming independence of occurrence and making some assumption concerning the outcome of their joint occurrence. Using these marginal mortalities, they calculated rates of irreplaceable mortality (“indispensable mortality”, Southwood 1978), i.e., the decrease in total mortality when a given mortality factor or group of factors is excluded from the life table. They compared irreplaceable mortalities for six categories of factors and found that irreplaceable mortality because of non-natural enemies (primarily abiotic factors) was significantly higher than that because of natural enemies. Characterizing irreplaceable mortality because of natural enemies as “very low”, they concluded that natural enemies typically have little impact on insect populations at temperate latitudes and in agricultural systems. They suggested that the impact of natural enemies may be higher in ecosystems with higher stability. They also presented an example based on Kuhar et al. (2002) of using irreplaceable mortality to assess the value of biological control agents. Unfortunately, problems with estimation and application of irreplaceable mortality weaken or invalidate their conclusions. It is important to consider proper usage of irreplaceable mortality because its misuse can result in misleading generalizations concerning insect ecology and in poor pest management decisions. ### Irreplaceable Mortality: Suitable Measure of the Effect of Mortality Factors on Population Growth Rate? Peterson et al. (2009) used irreplaceable mortality as a measure of the effect of mortality factors on population growth rate in comparisons among life tables. However, as pointed out by Bellows and Van Driesche (1999) and discussed in this section, irreplaceable mortality is generally inappropriate for such comparisons. For discrete generations, population growth rate is measured as the net multiplication rate per generation ( R …

Status ofCoccobiusnr.Fulvus(Hymenoptera: Aphelinidae), a Parasitoid of Euonymus Scale (Hemiptera: Diaspididae), 12–16 Years After Its Release in Massachusetts

From 1990 to 1995, a classical biocontrol pro gram was conducted in New England against an Asian scale, Unaspis euonymi (Comstock) (Hemi ptera: Diaspididae), which attacks landscape Eu onymus plants. Many Euonymus species are of Asian origin (Flint 1983) and widely planted as ornamentals (Gill et al. 1982). Collection of eu onymus scale natural enemies for release in the USA began in Korea (Drea & Hendrickson 1988; Hendrickson et al. 1991), but from 1990-1995 our laboratory collected additional species near Beijing, China (Van Driesche et al. 1998a), includ ing 2 predators (Chilocorus kuwanae Silvestri and Cybocephalus nr. nipponicus Endrody Younga) and 3 parasitoids (Coccobius nr. fulvus (Compere et Annecke), Encarsia nr. diaspidicola (Silvestri) and Aphytis sp.). Impacts of the 2 pred ators have been documented (Van Driesche et al. 1998b; Van Driesche & Nunn 2003). In 1991-1994, 3,862 adult C. nr. fulvus were re leased at 11 sites; 12,966 adults, nr. diaspidicola at 27 sites; and 801 adult Aphytis sp. at 5 sites in New England (mostly Massachusetts) (Van Drie sche et al. 1998a). By 1994, apparent establish ment (recovery in 1 subsequent year following re lease) had occurred for C. nr. fulvus and E. nr. di aspidicola. No next-year recoveries were made for Aphytis sp., the species released last and in small est numbers. No evidence of spread of any parasi toid was observed. In addition, a pre-existing cos mopolitan polyphagous aphelinid, Encarsia cit rina (Crawford), was observed in samples from Massachusetts. In 1991, it was detected at 44% of 79 sites in southern New England. In 1994, para sitism of dissected adult female euonymus scales by E. citrina, pooled by generation across 18 loca tions in Massachusetts, averaged 13.4% (n 2,174 scales) for the overwintered spring adults, 33.6% (n = 1,271 scales) for the summer generation, and 31.2% (n = 933 scales) for the fall generation. Our objectives here were (1) to sample for ex otic parasitoids of euonymus scale in western Massachusetts in 2006 and 2007 at their original release sites, (2) to sample non-release locations to detect parasitoid spread, and (3) to assess ef fects of exotic parasitoids on the pre-existing par asitoid E. citrina.

R. Van Driesche, M. Hoddle and T. Center, Control of pests and weeds by natural enemies. An introduction to biological control

R. Van Driesche, M. Hoddle and T. Center, Control of pests and weeds by natural enemies. An introduction to biological control

Environmental Impact of Invertebrates for Biological Control of Arthropods: Methods and Risk Assessment

F. Bigler, D. Babendreier, U. Kuhlmann. Environmental Impact of Invertebrates for Biological Control of Arthropods: Methods and Risk Assessment 2006 CABI Publishing Wallingford, Oxon, United Kingdom 299 0-85199-058-4 $126.00 Since the methodology of classical and augmentative arthropod biocontrol became formally recognized by pest managers at the beginning of the 20th century, concerns about the environmental impacts of natural enemy releases (also termed effects) have persisted. It was not until the late 1990s that these nontarget concerns were extensively debated among biocontrol practitioners, conservation biologists, and other public interest groups. Many studies and reviews addressing nontarget effects of biocontrol programs have since been published (Follett and Duan 2000, and reference therein). However, nontarget impact assessments for biocontrol have proven both technically and practically challenging. To date, there have been no standard methods and procedures to regulate and assess the risk of exotic invertebrate natural enemies (INEs) associated with arthropod biocontrol programs (van Driesche et al. 2001). This multi-authored book compiles 16 chapters and attempts to address the procedural and methodological issues related to regulation and environmental impact assessment of INEs for arthropod biocontrol programs. Specifically, this book addresses (1) prediction of host specificity of INEs; (2) assessment of indirect effects of INEs on target ecological communities through competition and secondary interactions such as interbreeding with existing natural enemy complexes; (3) determination of the dispersal and establishment potential at both field and regional scales; (4) prevention of …

ESTABLISHMENT OF A CHINESE STRAIN OF COTESIA RUBECULA (HYMENOPTERA: BRACONIDAE) IN THE NORTHEASTERN UNITED STATES

ESTABLISHMENT OF A CHINESE STRAIN OF COTESIA RUBECULA (HYMENOPTERA: BRACONIDAE) IN THE NORTHEASTERN UNITED STATES

Parasitoid Drift After Biological Control Introductions: Re-examining Pandora's Box

Howarth (1983) in his influential article “Classical biological control: panacea or Pandora's box” questioned the environmenta safety of biological control introductions. He focused on several important areas of concern including (1) the irreversibility of alien introductions, (2) the possibility of host switching to innocuous native or beneficial species, (3) dispersal of biological control agents to new habitats, and (4) the lack of research on the efficacy and impact of biological control attempts. Heightened concerns over nontarget effects since (Howarth 1991, Simberloff and Stiling 1996, Van Driesche and Hoddle 1997,Follett and Duan 1999) have slowed the pace of biological control introductions through increased regulation and have prompted a moment of reflection on the fate of past releases. The trend in biological control introductions is, perhaps, best exemplified in Hawaii, where more biological control releases have, been made against Insect pests than anywhere else in the world (Debach 1974, Funasaki et al. 1988). Largely in response to concerns over nontarget effects to Hawaii's unique and fragile fauna, introductions of parasitoids and predators against insect pests, which were being made at a rate of 3.8 speciesyr between 1900–1980, slowed to 2.3 speciesyr during 1980–1989 and have slowed further to about one introduction every two years since 1990 (Fig. 1). The lid to “Pandora's box” nearly has been shut tight in Hawaii.

Effects of Dipterous Parasitoids on Reproduction of Melanoplus sanguinipes (Orthoptera: Acrididae)

Densities of M. sanguinipes were estimated during spring and summer 1985 in two pastures (LI and HI) of crested wheatgrass. On each sampling date, adult females were collected and brought to the laboratory. Specimens were dissected to check for parasitoids and to determine the status of ovarian development. The parasitoids recorded were Diptera of the following species: Blaesoxipha reversa, B. hunteri, Sarcophaaa kellyi, S. opifora, Neorhynchocephalus sackenii, and Acridomyia canadensis. These parasitoids showed a complete temporal coincidence with adult M. sanguinipes populations. Observations suggest that when the female was parasitized at or before the beginning of vitellogenesis, the parasitoid probably prevented any egg development. Parasitism of females that had advanced egg development or eggs in the oviduct resulted in a high proportion of egg resorption (59%). Mathematical techniques were developed to estimate the proportion of mortality that was attributable to parasitoids, as well as absolute numbers of adult female grasshoppers that did or did not become parasitized. The estimated limits for genera- tional parasitism (GP) for all females were 15.5% to 15.8% for HI and 28.6% to 30.1% for LI. These results suggest that estimates of GP were not strongly affected by the precise moment when parasitism occurred. Diptera parasitoids are natural enemies of grasshopper populations (Greathead 1963, Rees 1973, York and Prescott 1952). The effect of such parasitism on survival, fecundity, and egg viability of individual Melanoplus sanguinipes (F.) in cages has been reported by Prescott (1960) and Rees (1986). However, the impact of parasitism on unconfined populations of grass- hoppers has not been extensively quantified. Most insect parasitoid studies use the percentage of parasit- ism observed in samples as an index of the impact of parasites as mortality factors in the host population. However, phenolo- gies of parasites and hosts might influence these percentages, making such values poor estimators of generational parasitoid affect (Van Driesche 1983, Van Driesche et al. 1991). Indeed, more detailed studies about host and parasitoid phenologies during the season are needed in order to improve the evalua- tion of parasitism. Phenologies of parasitoids and hosts were observed in this study, as well as the loss of host population oviposition poten- tial due to the effect of parasitoids. The objective was to better describe the impact of Diptera parasitism on M. sanguinipes survival and egg production.

Biological Control and Refuge Theory

REFERENCES tions arising from the intluences of host and parasitoid phenologies (3). Single values cannot characterize host-parasitoid interactions, and maximum values are unlikely to be typical over longer times or in different areas (4). 4) Contrary to the prediction made by Hawkins et al., successful biological control can result from the use of agents that are characterized by low rates of parasitization in their native habitat (5). Natural enemies that are rare in their native habitat may have superior potential as control agents when released in exotic habitats (6). 5) Hawkins et al. attribute seven cases of high parasitization (above 60%) in unsuccessful biological control projects to climatic mist,natch between parasitoids and hosts. We question how such high rates of parasitization could be achieved if clima tic factors reduce parasitoid reproduction, survivorship, or host synchrony ... (1, p. 1431). Variation in the susceptibility of insects to predators, parasitoids, and disease is important. Mechanisms for encapsulating parasitoids, hiding from predators, and resisting disease influence the impacts of natural enemies in native and exotic habitats, but measuring refuge size from the observed maximum parasitization of successful biological control programs does not yield new understanding or predictability to the practice of biological control. 1. B. A. Hawkins, M. B. Thomas, M. E. Hochberg, Science 262, 1429 (1993). 2. B. P. Beirne, Can. Entomo/. 107,225 (1975). 3. R. G. van Driesche, Environ. Entorno/. 12, 1611 (1983). 4. A. McPhee, A. Newton, K. B. McRae, Can. Entomo/.120, 73 (1988); l. A. Pearsall and S. J. Walde, Eco/. Entorno/. 19, 190 (1994). 5. J. Ro)and, in Popu/ation Dynamics of Forest /nsects, A. D. Watt, S. R. Leather, M. D. Hunter, N. A. C. Kidd, Eds. (Intercept, Andover, United Kingdom, 1990), pp. 289-302. 6. J. Myers, C. H. Higgins, E. Kovacs, Environ. Entorno/. 18, 541 (1989)

Biological Control and Refuge Theory

REFERENCES tions arising from the intluences of host and parasitoid phenologies (3). Single values cannot characterize host-parasitoid interactions, and maximum values are unlikely to be typical over longer times or in different areas (4). 4) Contrary to the prediction made by Hawkins et al., successful biological control can result from the use of agents that are characterized by low rates of parasitization in their native habitat (5). Natural enemies that are rare in their native habitat may have superior potential as control agents when released in exotic habitats (6). 5) Hawkins et al. attribute seven cases of high parasitization (above 60%) in unsuccessful biological control projects to climatic mist,natch between parasitoids and hosts. We question how such high rates of parasitization could be achieved if clima tic factors "reduce parasitoid reproduction, survivorship, or host synchrony ..." (1, p. 1431). Variation in the susceptibility of insects to predators, parasitoids, and disease is important. Mechanisms for encapsulating parasitoids, hiding from predators, and resisting disease influence the impacts of natural enemies in native and exotic habitats, but measuring refuge size from the observed maximum parasitization of successful biological control programs does not yield new understanding or predictability to the practice of biological control. 1. B. A. Hawkins, M. B. Thomas, M. E. Hochberg, Science 262, 1429 (1993). 2. B. P. Beirne, Can. Entomo/. 107,225 (1975). 3. R. G. van Driesche, Environ. Entorno/. 12, 1611 (1983). 4. A. McPhee, A. Newton, K. B. McRae, Can. Entomo/.120, 73 (1988); l. A. Pearsall and S. J. Walde, Eco/. Entorno/. 19, 190 (1994). 5. J. Ro)and, in Popu/ation Dynamics of Forest /nsects, A. D. Watt, S. R. Leather, M. D. Hunter, N. A. C. Kidd, Eds. (Intercept, Andover, United Kingdom, 1990), pp. 289-302. 6. J. Myers, C. H. Higgins, E. Kovacs, Environ. Entorno/. 18, 541 (1989)

Airborne drift residues collected near apple orchard environments due to application of insecticide mixtures

Substantial quantities of agriculturally applied pesticides have been shown to become airborne during and after application operations. This unwanted feature of pesticide usage, referred to as off-site pesticide drift, results not only in loss of pest control but may result in potential exposure to workers and other individuals near agricultural sites (Seiber et al. 1980). This has produced a wave of public concern and in many cases a very negative opinion of pesticide chemicals. The concern of both public and regulatory agencies about the deposition of pesticides outside the target area and the potential health effects due to this exposure situation has been termed "chemical trespass". In the northeastern United States, the problem of chemical trespass has been amplified due to the rather limited areas used for agricultural purposes and to the relatively high population densities which exist around them (Van Driesche et al. 1987).

Direct measurement of host and parasitoid recruitment for assessment of total losses due to parasitism in a continuously breeding species, the cabbage aphid,Brevicoryne brassicae(L.) (Hemiptera: Aphididae)

AbstractIn studies in Massachusetts, the population density ofBrevicoryne brassicae(L.) was measured over the lifespans of two groups of kale leaves from maturation to senescence, taking into consideration aphid spatial pattern (in colonies or as isolated insects) and aphid size as large (adults), medium-sized (nymphal instars 2–4) or small (first-instar nymphs) individuals. Total aphid densities per leaf in both leaf groups showed similar patterns of initial increase followed by a decrease as leaves aged over the 3–4-week period of leaf survival. Aphid densities reached peak values of 8·14 and 8·64 aphids per leaf for the two leaf groups studied, and 65–67% of all aphids observed occurred in colonies. Host and parasitoid recruitment to the aphid and the parasitoid immature populations were measured using a modification of the technique of Van Driesche & Bellows (1988). Total host recruitments per leaf were 43·7 and 64·6 aphids for the first and second leaf groups. Parasitoid recruitment was 6·8–8·1 for the first leaf group and 8·2–15·8 for the second. Recruitment values indicated 15·6–18.6% parasitism for the aphid cohort on the first leaf group and 12·7–24·4% for that on the second one.

Opportunities for Increased Use of Biological Control in Massachusetts. Edited by Roy Van Driesche and Eileen Carey. Research Bulletin No. 718, Massachusetts Agricultural Experiment Station, University of Massachusetts, and Massachusetts Department of Food and Agriculture. 141 pp.

Opportunities for Increased Use of Biological Control in Massachusetts. Edited by Roy Van Driesche and Eileen Carey. Research Bulletin No. 718, Massachusetts Agricultural Experiment Station, University of Massachusetts, and Massachusetts Department of Food and Agriculture. 141 pp.