Seedborne Pathogenic Fungi that Affect Seedling Quality of Red Angico (Anadenanthera macrocarpa) Trees in Brazil

Abstract

Internal and external seedborne fungal pathogens of Anadenanthera macrocarpa reduced seedling emergence and the quality of seedlings grown from contaminated seeds. Colletotrichum gloeosporioides, Fusarium lateritium, F. semitectum, Pestalotiopsis sp. and Phomopsis dalbergiae were the only fungi consistently isolated from seed samples collected from afforestation companies, university forestry departments and a Forest Reserve Park. Their frequency was much lower in surface disinfested than in untreated seeds. The temporal dynamics of the pericarp and seed infection on trees used for seed harvest in the Forest Reserve Park showed that colonization by these fungi starts soon after pod and seed formation, and continues to increase to pod maturity. Although the maximum proportion of infected seeds occurred at full maturity, their proportion was also high at physiological maturity. The high external seed infestation appears to occur during on-floor sun drying of the pods and separation of pericarps from seeds by broom sweeping. All five fungi were highly pathogenic to seeds and seedlings, causing seed rot, root rot and reduced height and thriftiness of surviving seedlings. Our results explain the heavy losses suffered by nurserymen due to low quality seedlings. This is the first report of the occurrence of these fungi on this host causing economical losses.

Detecção de fungos em sementes de pau-brasil (Caesalpinia echinata) coletadas durante sua formação e dispersão

“…Segundo Dhingra et al (2002), este fungo foi encontrado em associação com sementes de outras espécies florestais como Anadenanthera macrocarpa (Angico Vermelho), sendo altamente patogênico para as sementes e as plântulas, causando podridão na semente, podridão de raiz, redução na altura e definhamento de plântulas sobreviventes. Mendes e Muchovej (1991) relataram a presença de Pestalotiopsis maculans em folhas de pau-brasil, causando lesões claras, variando para marrom, no meio ou no bordo do folíolo.…”

Occurrence of Soil- and Tick-Borne Fungi and Related Virulence Tests for Pathogenicity to Ixodes scapularis (Acari: Ixodidae)

“…To investigate the virulence of locally isolated fungi, species used in the bioassays were previously reported to be virulent toward insects, acarids, or plants (Samsinakova et al 1974, Nentwig and Prillinger 1990, Kalsbeek et al 1995, Streekstra 1997, Dhingra et al 2002 Percentage mortality of ticks is based on the number of ticks that died of the 10 replicate ticks in each trial. *, Species name in bold signiÞes P Ͻ 0.05 based on log rank test.…”

Effects of Mycorrhizae and Nontarget Organisms on Restoration of a Seasonal Tropical Forest in Quintana Roo, Mexico: Factors Limiting Tree Establishment

“…Interestingly, this fungus is probably more of a facultative parasite, generally causing disease largely in introduced species (Domsch et al 1980). It is known to cause severe wilting disease in a leguminous tree Anadenanthera macrocarpa , planted in Brazil (Dhingra et al 2002). This was an interesting case in that the tree is naturally found in Brazilian primary or secondary forests in dry sandy or stony soil in a seasonal deciduous wet forest.…”

“…In northeastern Yucatan Peninsula, Glomus spp. predominated following fire compared with a diverse suite of fungi in the mature forest (Allen et al 2002, 2003 a ). But this response is not ubiquitous.…”