The effects of fenamiphos on soil and root populations of Pratylenchus
penetrans were evaluated in four red raspberry cv. Willamette fields in Northwestern
Oregon. Field 1 was a silty clay loam with 53% organic matter (OM). Field 2 and
3 were silty loam soils with 3.25 and 2.55% OM, respectively and field 4 was a silty
clay with 7.1% OM. The nematicide, fenamiphos (10 kg a.i./ha) was applied in
broadcast or band treatments on November 15, 1989. Additional plots in field 3,
received a band-nematicide treatment on December 28, 1989 to evaluate the effect
of application date on the control of P. penetrans in red raspberry. Field 4 had plots
in sites with and without grass and weed ground cover in the aisles between raspberry
rows to examine effects of ground cover on nematicide efficacy. Nematodes from
soil and roots were sampled monthly from all plots in each field from October 1989
to October 1990.
Soil populations of P. penetrans sampled within rows decreased between the
October and December sampling dates in all four fields. Soil populations in 3 fields
increased in density during mid-summer and reached their highest peak in the middle
of September. A similar pattern occurred in P. penetrans soil populations from plots
with or without ground cover in aisles between rows of raspberry in field 4.
However, in this field, numbers increased in July and reached their peak density in
August. Root populations of P. penetrans from red raspberry reached their highest
number during spring and summer at all fields.
No significant (P>0.05) differences in effectiveness of fenamiphos were
detected between band and broadcast method of application and, also between the
2 application dates. Seasonal mean densities of soil populations from band
application was only significantly lower than in nontreated controls in areas with
ground cover in field 4, respectively. High variability in the numbers of P. penetrans
in soil and roots of raspberry was observed throughout the year. Therefore,
conclusions about the effectiveness of fenamiphos were difficult to assess.
The efficiency of Baermann funnels was 43.9%, when a known number of P.
penetrans was added to soil. Total yields of P. penetrans extracted from raspberry
roots by mist chamber root extraction (MCRE) were higher (P = 0.05) than yields
extracted by polyethylene plastic bag root incubation (PBRI). Approximately 90% of
the total P. penetrans recovered was achieved after three and seven days of
extraction for PBRI and MCRE, respectively. However, the extraction efficiency of
MCRE was 30% higher than PBRI and the daily recovery lasted 28 and 18 days,
respectively. / Graduation date: 1992
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/37018 |
| Date | 15 March 1991 |
| Creators | Lolas, Mauricio |
| Contributors | Ingham, Russell E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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