Abstract
In Brazil, Meloidogyne mayaguensis has become a threat to guava production. Approximately a third of the cultivated area is infested, leading almost inevitably to the decimation of the orchards. Because parasitized trees develop rotten roots as the disease progresses, the possibility that a soil-borne pathogen could be involved was investigated. From several nematode-free or nematode-infested orchards, nearly 2000 root fragments were tested for bacteria and fungi. Positive isolations were obtained from nematode-infested areas only and were predominantly identified as Fusarium sp. In a 5-month microplot experiment, guava seedlings were uninoculated (control) or were inoculated with M. mayaguensis only or with this nematode and 21 days later with one of 11 Fusarium sp. isolates. A Scott–Knot analysis of several vegetative variables and of the extent of root rot allowed the generation of a dissimilarity dendrogram that indicated that four Fusarium sp. isolates were particularly associated with damage to the seedlings. Upon identification of these isolates as Fusarium solani, a 6-month microplot experiment was set up, in which guava seedlings were uninoculated or were inoculated with one of the following: (i) M. mayaguensis only, (ii) four F. solani isolates, separately, (iii) four F. solani isolates separately, combined with physical injury of the roots with a knife, (iv) M. mayaguensis, and 21 days later with four F. solani isolates, separately. No root rot and virtually no effect on all variables were observed in the seedlings inoculated with the fungus isolates, with or without physical injury. Major root rot and a negative effect on all variables were observed in the seedlings inoculated with M. mayaguensis and all four F. solani isolates. This characterizes guava decline as a complex disease caused by the synergistic effect of these organisms, in which parasitism by the nematode predisposes the plants to root decay caused by the fungus.
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Claims 6
Claim · model-written summary
About one third of cultivated guava area in Brazil was infested with the nematode, with orchard decimation.
- Taxon
- guava
Psidium guajavae0 - Interactor
- Meloidogyne mayaguensis
_5384315.jpg?width=60)
Meloidogyne enterolobiie0pathogen - Outcome
- cultivated area is infestede0
- Value
- Approximately a thirde0
- Setting
- Brazile0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_5384315.jpg?width=500)
Verbatim
e0“In Brazil, Meloidogyne mayaguensis has become a threat to guava production. Approximately a third of the cultivated area is infested, leading almost inevitably to the decimation of the orchards.”
Claim · model-written summary
Positive bacterial or fungal isolations occurred only from nematode infested orchards and were predominantly Fusarium sp.
- Taxon
- GuavaPsidium guajavat0
- Outcome
- Positive isolationse0
FusariumNot reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Positive isolations were obtained from nematode-infested areas only and were predominantly identified as Fusarium sp.”
t0“Guava Decline: A Complex Disease Involving Meloidogyne mayaguensis and Fusarium solani”
Claim · model-written summary
Four Fusarium isolates were particularly associated with seedling damage.
- Taxon
- GuavaPsidium guajavat0
- Outcome
- damage to the seedlingse0
- Value
- foure0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“four Fusarium sp. isolates were particularly associated with damage to the seedlings.”
t0“Guava Decline: A Complex Disease Involving Meloidogyne mayaguensis and Fusarium solani”
Claim · model-written summary
Fungal isolates alone or with physical root injury caused no root rot and virtually no effect on measured variables.
- Taxon
- GuavaPsidium guajavat0
- Treatment
- inoculated with the fungus isolatese0
- Interactor
- Fusarium solani
_Sacc._5393379.jpg?width=60)
Fusarium solanit0pathogen - Outcome
- root rot and virtually no effect on all variablese0
- Direction
- Noe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
_Sacc._5393379.jpg?width=500)
Verbatim
e0“No root rot and virtually no effect on all variables were observed in the seedlings inoculated with the fungus isolates, with or without physical injury.”
t0“Guava Decline: A Complex Disease Involving Meloidogyne mayaguensis and Fusarium solani”
Claim · model-written summary
Combined nematode and fungal inoculation caused major root rot and negative effects on all vegetative variables.
- Taxon
- GuavaPsidium guajavat0
- Treatment
- inoculated with M. mayaguensis and all four F. solani isolatese0
- Interactor
- M. mayaguensisMeloidogyne enterolobiie0pathogen
- Second interactor
- F. solaniFusarium solanie0pathogen
- Outcome
- root rot and a negative effect on all variablese0
- Direction
- negativee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Major root rot and a negative effect on all variables were observed in the seedlings inoculated with M. mayaguensis and all four F. solani isolates.”
t0“Guava Decline: A Complex Disease Involving Meloidogyne mayaguensis and Fusarium solani”
Claim · model-written summary
The authors attribute guava decline to nematode parasitism predisposing roots to fungus caused decay.
- Taxon
- guavaPsidium guajavae0
- Outcome
- root decaye0
- Qualifier
- parasitism by the nematode predisposes the plantse0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“guava decline as a complex disease caused by the synergistic effect of these organisms, in which parasitism by the nematode predisposes the plants to root decay caused by the fungus.”
The same questions in other papers
Meloidogyne enterolobii · disease · Psidium guajava (guava)Results agree
1 paper in the same direction as this paper
- negative
inoculation · disease · Psidium guajava (guava)Positive and negative results
5 papers in the same direction as this paper · 2 in the opposite direction
- no effect
- positive
- positive
4 papers more in this group
See all 8 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.