Abstract
Abstract Control of the Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae), with the entomopathogenic nematode Heterorhabditis marelata Liu and Berry (Nematoda: Heterorhabditidae) was examined in the laboratory and in potato fields in north central Oregon. This research tested the hypothesis that varying nitrogen fertilizer levels would affect foliar alkaloid levels, which would stress the host, and allow increased nematode reproduction and long‐term control of the CPB. Laboratory results indicated that nematodes tended to reproduce more readily in CPB fed on potato plants with high levels of fertilizer. Field trials tested CPB population responses to four treatments: application of nematodes vs. no nematodes, with application of low vs. high rates of nitrogen fertilizer. The higher nitrogen application rate increased field foliar levels of the alkaloids solanine by 35%, and chaconine by 41% over the season. Nematodes were applied twice during the season, causing a 50% reduction in adult CPB populations, and producing six times as many dead prepupae in nematode‐treated soil samples as in the untreated samples. However, no reproducing nematodes were found in the 303 dead prepupae and pupae collected from nematode‐treated plots. Nitrogen fertilizer levels, and their related alkaloid levels, did not affect nematode infection rates or reproduction in the field. Foliar alkaloid levels of plants from the growth chamber were 3–6‐fold as high as those in the field, which may explain the variation in nematode response to nitrogen applications to host plants of the CPB. Heterorhabditis marelata is effective for controlling CPB in the field, and does not have negative non‐target effects on one of the most common endemic CPB control agents, Myiopharus doryphorae (Riley) (Diptera: Tachinidae), but the low rate of nematode reproduction cannot be manipulated through alkaloid stress to the beetle. Until H. marelata can be mass‐produced in an inexpensive manner, it will not be a commercially viable control for CPB.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 11
Claim · model-written summary
Nematodes tended to reproduce more readily in beetles fed high-fertilizer potato plants in the lab.
- Taxon
- potato
Solanum tuberosume0 - Treatment
- high levels of fertilizere0
- Interactor
- CPBe0pest
- Outcome
- nematodes tended to reproduce more readily in CPBe0
- Direction
- more readilye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nematodes tended to reproduce more readily in CPB fed on potato plants with high levels of fertilizer”
Claim · model-written summary
Higher nitrogen increased foliar solanine by 35%.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- higher nitrogen application ratee0
- Outcome
- field foliar levels of the alkaloids solaninee0
- Direction
- increasede0
- Value
- 35%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The higher nitrogen application rate increased field foliar levels of the alkaloids solanine by 35%”
t0“potato plant”
Claim · model-written summary
Higher nitrogen increased foliar chaconine by 41%.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- higher nitrogen application ratee0
- Outcome
- chaconinee0
- Direction
- increasede0
- Value
- 41%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The higher nitrogen application rate increased field foliar levels of the alkaloids solanine by 35%, and chaconine by 41% over the season”
t0“potato plant”
Claim · model-written summary
Nematode applications reduced adult beetle populations by 50%.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Nematodes were applied twicee0
- Interactor
- CPBe0pest
- Second interactor
- Heterorhabditis marelatat0biocontrol_agent
- Outcome
- adult CPB populationse0
- Direction
- reductione0
- Value
- 50%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nematodes were applied twice during the season, causing a 50% reduction in adult CPB populations”
t0“Heterorhabditis marelata and potato plant”
Claim · model-written summary
Treated soil samples had six times as many dead beetle prepupae.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- nematode‐treatede0
- Interactor
- Colorado potato beetle
Leptinotarsa decemlineatat0pest - Second interactor
- Heterorhabditis marelatat0biocontrol_agent
- Outcome
- dead prepupaee0
- Direction
- six times as manye0
- Value
- six timese0
- Comparator
- untreated samplese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“producing six times as many dead prepupae in nematode‐treated soil samples as in the untreated samples”
t0“Colorado potato beetle control by application of the entomopathogenic nematode Heterorhabditis marelata and potato plant”
Claim · model-written summary
No reproducing nematodes occurred in 303 dead prepupae and pupae from treated plots.
- Taxon
- potatoSolanum tuberosumt0
- Interactor
- Colorado potato beetleLeptinotarsa decemlineatat0pest
- Second interactor
- Heterorhabditis marelatat0biocontrol_agent
- Outcome
- no reproducing nematodes were founde0
- Value
- 303 dead prepupae and pupaee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no reproducing nematodes were found in the 303 dead prepupae and pupae collected from nematode‐treated plots”
t0“Colorado potato beetle control by application of the entomopathogenic nematode Heterorhabditis marelata and potato plant”
Claim · model-written summary
Nitrogen fertilizer did not affect nematode infection or reproduction in field trials.
- Taxon
- potatoSolanum tuberosumt0
- Treatment
- Nitrogen fertilizer levelse0
- Interactor
- Heterorhabditis marelatat0biocontrol_agent
- Outcome
- nematode infection rates or reproductione0
- Direction
- did not affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Nitrogen fertilizer levels, and their related alkaloid levels, did not affect nematode infection rates or reproduction in the field”
t0“Heterorhabditis marelata and potato plant”
Claim · model-written summary
Growth-chamber foliage had 3–6-fold higher alkaloids than field foliage.
- Taxon
- potatoSolanum tuberosumt0
- Outcome
- Foliar alkaloid levelse0
- Direction
- as high ase0
- Value
- 3–6‐folde0
- Comparator
- the fielde0
- Setting
- growth chambere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Foliar alkaloid levels of plants from the growth chamber were 3–6‐fold as high as those in the field”
t0“potato plant”
Claim · model-written summary
H. marelata did not harm the endemic beetle control agent Myiopharus doryphorae.
- Taxon
- potatoSolanum tuberosumt0
- Interactor
- Myiopharus doryphorae
Myiopharus doryphoraee0biocontrol_agent - Outcome
- negative non‐target effectse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“does not have negative non‐target effects on one of the most common endemic CPB control agents, Myiopharus doryphorae”
t0“potato plant”
Claim · model-written summary
The authors conclude low nematode reproduction cannot be manipulated through beetle alkaloid stress.
- Taxon
- potatoSolanum tuberosumt0
- Interactor
- beetlee0pest
- Outcome
- low rate of nematode reproduction cannot be manipulatede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the low rate of nematode reproduction cannot be manipulated through alkaloid stress to the beetle”
t0“potato plant”
Claim · model-written summary
The authors conclude H. marelata is not commercially viable until inexpensive mass production is possible.
- Taxon
- potatoSolanum tuberosumt0
- Interactor
- CPBe0pest
- Second interactor
- H. marelatae0biocontrol_agent
- Outcome
- will not be a commercially viable control for CPBe0
- Qualifier
- Until H. marelata can be mass‐produced in an inexpensive mannere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Until H. marelata can be mass‐produced in an inexpensive manner, it will not be a commercially viable control for CPB”
t0“potato plant”
The same questions in other papers
fertilization · disease · Solanum tuberosum (potato)Positive and negative results
14 papers in the same direction as this paper · 33 in the opposite direction
- positive
- positive
- positive
44 papers more in this group
See all 48 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.