ability to survive in the soil for many years and are very difficult to control ( Bost, 2006 ; Bost et al., 2013 ). Biological control agents (BCAs) can be helpful in decreasing the soil inoculum potential of soilborne pathogens and therefore improve soil
Jacqueline Joshua and Margaret T. Mmbaga
Jeffery W. Marvin, Robert Andrew Kerr, Lambert B. McCarty, William Bridges, S. Bruce Martin, and Christina E. Wells
. Chlorothalonil (2 kg a.i./ha) and AzP (0.4 kg a.i./ha) were considered quarter label rate. Biological control agents were BS formulated as Rhapsody SC; EO clove oil + wintergreen oil + thyme oil formulated as Paradigm L; extract of RS formulated as Regalia L; and
V. Bruce Steward, Janet L. Kintz, and Tracy A. Horner
Biological control agents were ordered from three U.S. suppliers three times during 1994 and were evaluated (total of nine orders evaluated). Biological control agents evaluated were a whitefly parasitoid [Encarsia formosa Gahan (Hymenoptera: Aphelinidae)], mealybug destroyer [Cryptolaemus montrouzieri Mulsant (Coleoptera: Coccinellidae)], insidious flower bug [Orius insidiosus (Say) (Heteroptera: Anthocoridae)], and a predatory mite [Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae)]. Arrival time, packaging methods, cost, quality, and quantity for each shipment were recorded. Six of the nine orders evaluated did not arrive by the date promised by the supplier. Most biological control agents were shipped in styrofoam boxes; the method by which they were packed in the box differed among suppliers. The cost of each biological control agent order ranged from $260.64 to $327.03 and varied with the same supplier. The number of viable E. formosa emerging ranged from 745 to 4901; two of the nine orders met the quota of 2000 live wasps. The total number of live C. montrouzieri received ranged from 234 to 288; five orders contained the expected number of 250 live beetles. For the expected order of 1000 O. insidiosus, quantities of live insects ranged from 423 to 1333; three orders contained at least the expected amount. The number of live P. persimilis ranged from 199 to 4447. Three orders contained the targeted amount of 2000. Our findings indicate that there are problems with the quantity of viable biological control agents being shipped. To build consumer confidence in the potential effectiveness of biological control, suppliers and producers of biological control agents must address ways to ensure that the consumer receives a high-quality product, in quantity and viability.
M. Little, W. Brown, T.J. Blom, J.A. Gracia-Garza, K. Schneider, W. Allen, and J. Potter
Pythium root rot (Pythium spp.) is a common disease of greenhouse-grown poinsettias (Euphorbia pulcherrima) that can cause serious plant loss or reduction in plant quality. Application of effective chemical fungicides to poinsettia plants has reduced losses due to Pythium; however, development of resistance to these fungicides is a legitimate concern, as well as the environmental implications of using chemical pesticides. In this study, a group of products of biological origin and known biocontrol agents were evaluated for their efficacy to control pythium root rot of poinsettia. These products and organisms were compared to metalaxyl (Ridomil), a fungicide commonly used to reduce losses to Pythium. The results showed that two products based on two different species of Streptomyces, Mycostop and Actino-Iron, were as effective as metalaxyl at reducing the symptoms associated with pythium root rot when artificially inoculated with Pythium ultimum var. ultimum compared to the control plants. Many roots remained functional throughout the duration of the experiments and the overall appearance and number of bracts of commercial quality of the plants were similar for the three treatments mentioned above. In an additional experiment, Mycostop was tested in combination with a single application of metalaxyl either at 3, 7, or 11 weeks after transplanting. Plants inoculated with P. ultimum var. ultimum and treated with metalaxyl either on week 3 or 7 after transplanting in combination with two applications of Mycostop, had greater fresh root weight than those only treated with metalaxyl at week 11 or the chemical control (three applications of metalaxyl). However, there was no significant difference in the number of bracts or the bract diameter between plants treated with metalaxyl at weeks 3 or 7 followed by Mycostop and those plants treated with the fungicide alone. A reduction in the amount of fungicide used to control pythium root rot can be achieved when used in combination with a biocontrol agent without compromising the health of poinsettias.
A genetically engineered, bioluminescent strain of Xanthomonas campestris pv. campestris (Xcc) was used to study the effectiveness of plant growth-promoting rhizobacteria (PGPR) as disease control agents. Black-rot-susceptible cabbage plants were wound-inoculated with PGPR and wound- or mist-inoculated with bioluminescent Xcc 10 days later. Growth of the bioluminescent strain in the plants was followed over time with a low-light, charge-coupled device camera. Several PGPR strains effectively reduced growth of the bioluminescent pathogen in the plants when bacteria were introduced into the plant by wound. PGPR inoculation was less effective when bioluminescent bacteria were introduced into the plant by mist inoculation. Little effect on symptom reduction was observed.
Mathews L. Paret, Asoka S. de Silva, Richard A. Criley, and Anne M. Alvarez
complex APS Press St. Paul, MN Anderson, R.C. Gardner, D.E. 1996 Preliminary evaluation of Pseudomonas solanacearum as a potential biological control agent of the alien weed kahili ginger ( Hedychium gardenarium ) in Hawaiian forests Nwsl. Hawaiian Bot
Erick X. Caamano, Raymond A. Cloyd, Leellen F. Solter, and Declan J. Fallon
Entomopathogenic nematodes (EPN) are used as biological control agents to regulate a variety of insect pests ( Chyzik et al., 1996 ; Georgis et al., 2006 ; Gouge and Hague, 1995 ; Hara et al., 1993 ; Oguzoglu and Ozer, 2003 ). The two most
Michael A. Norman, Kim D. Patten, and Sarangamat Gurusiddaiah
Three indicator species [rye (Secale cereale L.), radish (Raphanus sativus L.), and alfalfa (Medicago sativa L.)] and nonrooted cuttings of `Stevens' cranberry (Vaccinium macrocarpon Ait.) vines were grown in pots to establish the dose response levels for a sand-applied phytotoxin(s) from a crude extract of Pseudomonas syringae (strain 3366) culture. At 114 ppm [milligrams phytotoxin(s)/kilograms sand], the material was noninhibitory, whereas 1140 ppm reduced root and shoot growth significantly in all four species. In subsequent experiments, a 10-ppm dose controlled corn spurry (Spergula arvensis L.) and fireweed (Epilobium angustifolium L.) seedlings, while 103 ppm reduced root or shoot growth of cuttings of the perennial weeds birdsfoot trefoil (Lotus corniculatus L.) and silverleaf (Potentilla pacifica Howell). Root and shoot growth of partially rooted `McFarlin' cranberry vines was reduced at 103 and 563 ppm, respectively. The phytotoxin(s) could potentially control germinating annual weeds in newly established `Stevens' cranberry bogs.
Thomas E. Marler, Ross Miller, and Aubrey Moore
agent. The causes of reduced scale predation by R. lophanthae near the ground are unknown, but a parasitoid biological control agent may not exhibit these same limitations. Furthermore, because a parasitoid would be much smaller than R. lophanthae
Amy L. Raudenbush, Raymond A. Cloyd, and Erik R. Echegaray
available compounds ( Lindquist et al., 1985 ). Biological control agents such as the rove beetle, Dalotia coriaria Kraatz (Coleoptera: Staphylinidae), have been shown to be an effective predator against fungus gnat larvae ( Carney et al., 2002