). However, there are unsubstantiated allegations made by a manufacturer that certain plant-growing media containing B. pumilus and an arbuscular mycorrhizal fungus, Glomus intraradices , negatively affect the survival of western flower thrips pupae and
Three sites (A-C) were prepared for citrus groves in Florida from 1985 to 1986. Nine soil amendments applied at either one or two rates were deep-tilled 3.9 to 4.9 ft (1.2 to 1.5 m) deep and 4.9 ft (1.5 m) wide in the row before planting. Maximum treatment rates were limestone 50,000 at lb/acre (56 000 kg·ha−1), phosphoclay at 80,000 lb/acre (89 600 kg·ha−1), humate at 77,612 lb/acre (86 912 kg·ha−1), shrimp waste at 73,052 lb/acre (81 805 kg·ha−1), peat at 250,000 lb/acre (280 000 kg·ha−1), bentonite clay at 73,051 lb/acre (81 805 kg·ha−1), mined gypsum at 2000 lb/acre (2240 kg·ha−1), calcium humate at 2000 lb/acre (2240 kg·ha−1), and phosphogypsum at 10,000 lb/acre (11 200 kg·ha−1). Deep-tilled controls and a no-till control were established at sites A and B and a deep-tilled control at site C. A fourth grove (site D) was planted in 1970 and included the treatments surface tillage (ST), deep tillage (DT), and DT plus lime (DTL) at 45,407 lb/acre (50,848 kg·ha−1). Mycorrhizal fungus infection was found in roots in 1987 at sites A and B and in 1989 in site C. Fungus infection ranged from 6% (no-till control) to 64% at site A, 64% to 81% at site B, and 15% to 47% at site C. At all sites, amendments did not increase percentage infection and vesicle and hyphae ratings significantly over the deep-tilled control. At site A, percentage infection in the limestone treatment was the highest (64%) and was significantly higher than infection in phosphogypsum, peat, and the no-till control treatments. No treatment had a suppressive effect on infection. Mycorrhizal infection in roots was high (94% to 95%) at site D but did not differ significantly between treatments.
Tomohiro Okada and Yoh-ichi Matsubara
weeks after AMF inoculation. None = none–AMF-inoculated; AMF+ = Glomus sp. R10. Bars represent se s (n = 10). *significantly different between non-AMF and AMF plants ( t test, P ≤ 0.05); ns = non-significant. AMF = arbuscular mycorrhizal fungus
Abu Shamim Mohammad Nahiyan and Yoh-ichi Matsubara
conidial suspension onto the soil. Evaluation of arbuscular mycorrhizal fungus colonization level. Ten weeks after AMF inoculation and 8 weeks after Foa inoculation, roots of asparagus were preserved with 70% ethanol and stained according to Phillips and
Carolyn F. Scagel and Jungmin Lee
influence of AMF on production of phenolics in basil is related to AMF-mediated effects on whole plant nutrient status. Materials and Methods Plant materials and arbuscular mycorrhizal fungus inoculum. Four basil cultivars (Cinnamon, Siam Queen, Sweet Dani
Carolyn F. Scagel, David R. Bryla, and Jungmin Lee
treatments were also inoculated or not with the arbuscular mycorrhizal fungus (+AMF), Rhizophagus irregularis ). Symbols represent the mean of ( A , B ) 40 (41 d) and 24 (75 d) replicates and ( C , D ) five replicates and error bars represent the least
D.D. Douds Jr., G. Bécard, P.E. Pfeffer, L.W. Doner, T.J. Dymant, and W.M. Kayser
A vesicular–arbuscular mycorrhizal fungus in a peat-based medium significantly increased survival, callus development, and rooting percentage of Sciadopitys verticillata cuttings over noninoculated cuttings. The presence of a nurse host plant for the mycorrhizal fungi to colonize in the absence of S. verticillata roots decreased survival and rooting percentage, but not callus development, relative to the fungus without the nurse host. Among plants that did produce roots, however, there were no significant differences among treatments for root number, weight, or length per cutting.
M.T. Vidal, C. Azcón-Aguilar, J.M. Barea, and F. Pliego-Alfaro
Micropropagated plantlets of avocado (Persea americana Mill.) exhibit a very slow rate of growth during the acclimatization phase, possibly because mycorrhizae are absent. Inoculation of plantlets with the vesicular-arbuscular mycorrhizal fungus Glomus fasciculatum (Thaxter sensu Gerd) Gerd and Trappe improved formation of a well-developed root system that was converted into a mycorrhizal system. Introduction of the mycorrhizal fungus at the time plantlets were transferred from axenic conditions to ex vitro conditions improved shoot and root growth; enhanced the shoot: root ratio; increased the concentration and/or content of N, P, and K in plant tissues; and helped plants to tolerate environmental stress at transplanting. Inclusion of soil as a component of the potting medium appeared to favor mycorrhiza formation and effectiveness. Thus, mycorrhiza formation seems to be the key factor for subsequent growth and development of micropropagated plants of avocado.
Laura L. Arriola, Mary K. Hausbeck, John Rogers, and Gene R. Safir
Commercially available biocontrol agents Trichoderma harzianum Rifai and the arbuscular mycorrhizal fungus Glomus intraradices Schenck and Smith were tested for their efficacy in controlling fusarium root rot in potted asparagus (Asparagus officinalis L.) seedlings. High and low concentrations of Fusarium oxysporum (Schlect.) emend. Snyd. & Hans. f. sp. asparagi Cohen & Heald (FOA) were combined with G. intraradices and/or T. harzianum treatments. In both experiments included in this study, T. harzianum and G. intraradices alone and in combination effectively reduced root rot caused by FOA when asparagus seedlings were grown in low levels of FOA-infested medium. When seedlings were grown in high levels of FOA-infested medium, the combination of T. harzianum + G. intraradices significantly increased dry shoot mass and limited root rot compared to the control.
Jorge Pinochet, Carolina Fernández, María de Carmen Jaizme, and Pedro Tenoury
The effects of the interaction between the vesicular-arbuscular mycorrhizal fungus Glomus intraradices Schenk and Smith and the root-knot nematode Meloidogyne javanica (Treub) Chitwood on growth and nutrition of micropropagated `Grand Naine' banana (Musa AAA) were studied under greenhouse conditions. Inoculation with G. intraradices significantly increased growth of plants in relation to nonmycorrhizal plants and was more effective than P fertilization in promoting plant development. Mycorrhizal colonization did not affect nematode buildup in the roots, although plants with the nematode and mycorrhiza were more galled. Meloidogyne javanica had no effect on the percentage of root colonization in mycorrhiza-inoculated plants. No element deficiency was detected by foliar analysis. All elements were within sufficiency levels for banana with exception of N, which was low. Potassium levels were lower in mycorrhizal plants, while Ca and Mg levels were higher with mycorrhiza than without, with or without the nematode. Early inoculation with G. intraradices appears to favor growth of banana plants by enhancing plant nutrition.