Laboratory host range testing
Pathogen biological control agents
Alaphilippe A., Elad Y., David D.R., Derridj S. and Gessler C. (2008).
Effects of a biocontrol agent of apple powdery mildew (Podosphaera leucotricha) on the host plant and on non-target organisms: an insect pest (Cydia pomonella) and a pathogen (Venturia inaequalis).
Biocontrol Science and Technology 18: 121-138
Non-target effects of sprayed applications of a potential biocontrol agent, an epiphytic yeast isolate called Y16, of apple powdery mildew Podosphaera leucotricha Ell. Et Ev.), on scab infections (Venturia inaequalis Cooke Winter), on codling moth oviposition and damage and apple quality were examined. The BCA affected neither conidia germination of V. inaequalis nor their penetration of the leaf tissue but suppressed the disease caused by this pathogen. The quantity of eggs laid by the codling moth during its second flight period on yeast treated trees was significantly different, but inconsistent from year to year, the differences attributed to year-to-year variation in environmental conditions, which may affect yeast survival and activity. A 2-month-long assay was conducted in the orchard during the codling moth's second flight period from mid-July until mid-September. The yeast treatment did not affect the damage caused by the codling moth to the fruits or any of the examined fruit quality parameters.
Bailey, K.L., Pitt, W.M., Falk, S. and Derby, J. (2011). The effects of Phoma macrostoma on nontarget plant and target weed species. Biological Control 58: 379-386
Berner D.K., Bruckart W.L., Cavin C.A., Michael J.L., Carter M.L. and Luster D.G. (2009).
Best linear unbiased prediction of host-range of the facultative parasite Colletotrichum gloeosporioides f. sp salsolae, a potential biological control agent of Russian thistle.
Biological Control 51(1): 158-168.
Russian thistle or tumbleweed (Salsola tragus L.) is an introduced, widely distributed invasive weed in N. America. The fungus Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. in Penz. f. sp. salsolae (CGS) is a facultative parasite being considered for classical biological control of this weed. Host-range tests were conducted with 92 accessions from 19 families of plants including 62 genera and 120 species. Disease reaction data were combined with a relationship matrix derived from internal transcribed spacer DNA sequences and analyzed with mixed model equations to produce Best Linear Unbiased Predictors (BLUPs) for each species. Twenty-nine species (30 accessions) from seven closely-related Chenopodiaceae tribes had significant levels of disease severity as indicated by BLUPs, compared to six species determined to be susceptible with least squares means estimates. Of the 29 susceptible species, 10 native or commercially important species in N. America were identified as needing additional tests to determine the extent of any damage caused by infection.
Dhileepan K., Lockett C.J., Balu A., Murugesan S., Perovic D.J. and Taylor D.B.J. (2015). Life cycle and host range of Phycita sp. rejected for biological control of prickly acacia in Australia. Journal of Applied Entomology 139: 800-812.
Gilbert G.S. and Webb C.O. (2007).
Phylogenetic signal in plant pathogen-host range.
Proceedings of the National Academy of Sciences of the United States of America 104: 4979-4983
Susceptibility of plant species plant pathogens is poorly understood. Most fungal pathogens are usually polyphagous but most plant species in a local community are resistant to any given pathogen. The probablility that a pathogen can infect two plant species decreases continuously with phylogenetic distance between the plants. This allows prediction of the likely host range of plant pathogens in a local community. The results suggest that the rate of spread and ecological impacts of a disease through a natural plant community depends on the phylogenetic structure of the community itself and that current regulatory approaches strongly underestimate the local risks of global movement of plant pathogens or their hosts.
Hoagland R.E., Weaver M.A. and Boyette C.D. (2007).
Myrothecium verrucaria fungus: a bioherbicide and strategies to reduce its non-target risks.
Allelopathy Journal 19: 179-192
The herbicidal activity of an M. verrucaria (MV) strain originally isolated from sicklepod (Senna obtusifolia) was evaluated against kudzu (Pueraria lobata) and several other weeds. Tests showed high levels of efficacy of MV and a large range of nontarget, young, woody plant species from several plant families ranged from non-susceptible to moderately susceptible. Although MV possesses desirable bioherbicidal traits, this isolate also produces undesirable mycotoxins, i.e. trichothecenes. Future approaches to possibly reduce or eliminate these mycotoxins are discussed.
Poulton J., Markwick N.P., Ward V.K. and Young V. (2007).
Host range testing of a nucleopolyhedrovirus of the lightbrown apple moth, Epiphyas postvittana.
New Zealand Plant Protection 60: 26-32
Epiphyas postvittana nucleopolyhedrovirus (EppoNPV) has potential as a biopesticide for control of lightbrown apple moth and non-target impacts were investigated. Eight non-target insect species from one hymenopteran and five lepidopteran families were inoculated with EppoNPV. Larval survival, growth rates, pupation and pupal weights were measured and larvae examined for virus. Few viral infections were found, growth and survival were compromised in virus-fed individuals in only one species, Tyria jacobaeae, where the majority of larvae had high microsporidal infections. EppoNPV polyhedra were found in only one larva, suggesting a very low likelihood of field infectivity.
Retief E., Rooi C. van, and Breeyen A. den (2016). Environmental requirements and host-specificity of Puccinia eupatorii, a potential biocontrol agent of Campuloclinium macrocephalum, in South Africa. Australasian Plant Pathology 45: 135-144
Weidemann G.J. (1991).
Host-range testing: safety and science.
Pp. 83-96 In: Microbial control of weeds, D.O. TeBeest (Ed.) Chapman and Hall Ltd, London, UK.
The review concludes that whilst phylogenetic based testing is useful it is not a completely predictable system. Genetic variation in hosts and pathogens must be taken into account in the design of future tests and this requires greater understanding of host specificity, adaptation and genetic diversity.
Yanek M.L. and Raffa K.F. (2008).
Evaluation of Gypchek and its carrier on various Lepidoptera species under laboratory conditions.
Great Lakes Entomologist 41: 27-39
Gypchek is a gypsy moth-specific nucleopolyhedrosis virus applied in conjunction with Carrier 038-A, a surfactant and sunscreen. Carrier 038-A alone and with Gypchek was tested on an endangered species, the Karner blue butterfly ( Lycaeides melissa samuelis Nabokov), tobacco hornworm ( Manduca sexta L.), L. dispar , and seven other Lepidoptera species. Where there was evidence of nontarget effects with a high dose the authors continued with a method to approximate field application. Eight species were unaffected. Gypsy moth was sensitive to Gypchek as expected but not to its carrier, and L. m. samuelis showed putative effects which warranted further testing. With simulated field spray-deposition, there was no impact of carrier 038-A or Gypcheck with carrier on L. m. samuelis larvae. The authors further concluded that the partial canopy cover of oak savannas and partially asynchronous phenology with L. dispar would reduce exposure to L. m. samuelis .
Weed biological control agents
Predatory biological control agents