s5- IFAS NFREC Research Report 95:4












INFLUENCE OF PLANTING DATE AND VARIETY ON DAMAGE DUE TO
MELOIDOGYNE ARENARIA IN PEANUT




Marston Science
Library
APR 18 1995

University of Florida


Jimmy R. Rich
University of Florida
Route 3, Box 4370
Quincy, FL 32351


Daniel W. Gorbet
University of Florida
Route 3, Box 376
Marianna, FL 32446


Stacey K. Barber
University of Florida
Route 3, Box 4370
Quincy, FL 32351









INTRODUCTION

The root-knot nematode, Meloidogyne arenaria, is one of the most serious

soilborne pests of peanut in North Florida. Crop rotation and nematicides are

management tools which reduce but do not prevent losses from this pest. Other

management techniques need to be developed to further reduce losses due to

nematodes in peanut. Studies in other crops have indicated yield benefits by altering

planting dates and utilizing shorter season varieties. The trial reported herein was

conducted to determine the effect of three planting dates and two varieties of peanut

on yield loss caused by the peanut root-knot nematode.

MATERIALS AND METHODS

A field trial was conducted on a Chipola loamy sand soil at the North Florida

Research and Education Center, Marianna in 1994. The field was previously planted

to grain sorghum in 1993. The site was moldboard plowed and doubled disced in late

March. Treatments in the test included three planting dates (April 25, May 16, June

9), two peanut varieties (Florunner and Marc I), and a nematicide (with or without

Temik 15G). Planting dates served as the mainplots, varieties as subplots, and

nematicide treatment (Temik vs none) as sub-subplots. Planting date plots were

replicated three times. Temik 15G application was made at-planting in a modified-

infurrow, 8" band over the row at the rate of 10 Ibs. formulation/acre. The Temik

15G subplots were two rows (36" wide) by 20' long. An additional "at-pegging"

treatment with 10 Ibs. formulation of Temik was made 85 days after planting.

Standard cultural practices were utilized over the season, and the two peanut varieties

were harvested according to average days to and visual indication of maturity.









After harvest, in-shell peanuts were dried to 10% moisture, weighed and yield

converted to Ibs./A. Nematode samples were taken at harvest by removing six soil

cores (1" dia.) to a depth of 10" in each plot. Samples from individual plots were

composite and 100 cm3 soil extracted by the sugar-flotation, centrifugation

technique.

RESULTS

Yield of peanut was significantly higher when planted April 25 and May 16

compared to June 9 (Table 1). Nematode numbers, however, were lowest at the June

9 planting date. Temik treatment significantly improved peanut yield at two of the

three planting dates (April 25, May 16) in both peanut varieties (Table 2). No

significant yield differences were found between the Marc I and Florunner variety at

any planting date or with and without Temik treatment. Number of nematodes were

significantly reduced by the Temik treatments in the first two planting dates (Table 2).

When comparing Temik and nontreated plots at each planting date, the percentage

yield loss was lowest on June 9 in both the Marc I and Florunner. Average number

(Temik plus nontreated) of nematodes were lowest on June 9 in the Florunner.

DISCUSSION

These data and those from 1993 support the hypothesis that late planting dates

can reduce losses caused by the peanut root-knot nematode. Lower yields at the

June 9 date may, however, indicate that this late planting is not advantageous

agronomically. The late plantings are commonly under more disease pressure from

leaf spots, rust and soil-borne diseases. Further work needs to be conducted under

more controlled conditions such as microplots to follow nematode populations more

extensively and more precisely determine planting date and yield interactions.









Table 1. Influence of planting data on peanut yield and number of peanut root-

knot nematode in a field test, 1994.


Plant Date Yield in Ibs./a No. Nematodesy


April 25 4000a' 387a


May 16 3838a 526a


June 9 2909b 209a


Y Number of nematodes extracted from 100 cm3 soil.


SColumn means followed by the same letter are not different (P : 0.05)

according to Duncan's multiple range test.









Table 2. Influence of Temik 15G treatment on peanut yield and number of

peanut root-knot nematodes in a field test, 1994.


Yield in Ibs./A at Planting Dates


Treatment April 25 May 16 June 9


Temik 4349ay 4329a 2912a


Control 3461 b 3347b 2584a


Nematode Numbers


Temik 179a 348a 444a


Control 820b 704b 267a


Y Column means followed by the same letter are not different (P 0.05)

according to analysis by ANOVA.

z Nematodes extracted from 100 cm3 soil.




* I I r


Table 3. Percentage yield loss and number of nematodes in two peanut varieties

affected by the peanut root-knot nematode in a field trial, 1994.


Variety and Planting Date % Yield Loss No. Nematodesz


Marc I


April 25 21 435


May 16 38 357


June 9 11 371


Average


Florunner


April 25 19 339


May 16 21 695


June 9 10 190


Nematodes extracted from 100 cm3 soil.