1971] HAWKINS AND MILLER: MEADOW NEI~fATODE CON~rROL 21

R O W T R E A T M E N T OF P O T A T O E S W I T H S Y S T E M I C S F O R M E A D O W N E M A T O D E ( P R A T Y L E N C H U S P E N E T R A N S )

C O N T R O L

ARTHUR HAWKINS 1 AND P, ~{. MILLER 2

ABSTRACT

Granular aldicarb and carbofuran, systemic carbamate insecticides, were applied at 3 lbs active per acre to compare their control of the meadow nematode (Pratylenchus penetrans). These systemic pesticides were applied either in two bands 2-3 inches from both sides of and at the lower plane of the seed-piece or in one band 4-5 inches wide and inch above the seed. Two months after planting, nematode populations were greatly reduced in soil and roots from plots treated with either chemical and with both placement methods. Aldicarb provided effective control longer into the growing season than did carbofuran. When com- pared with carbofuran, aldicarb-treated potao plants lived longer and produced a greater increase in yield over the untreated plots. Yield in- creases were greater when either systemic was applied in side hands than when placed over the seed.

Where granular aldicarb, (Temik)| a systemic carbamate insecticide had been applied with the fertilizer bands at planting in 1966, larger rifles, growth later in the season, and increased yields of potatoes were noted. The response did not appear to be due to insect control, since insects were adequately controlled by spraying with insecticides in the adjoining rows.

The object of the study conducted in 1968 was to determine the effects of applications of the systemic insecticide-nematicides, aldicarb (Temik) | and carbofuran (Furadan) | when placed over the row and in side bands on control of the meadow nematode (Pratylenchus penetrans), plant response and yield of potatoes. Neither aldicarb nor carbofuran is now cleared for use on potatoes, but information is needed on their use in potatoes in the event their use is permitted.

MATERIALS AND I~{ETHODS

The test was located in the Connecticut River Valley in a commercial potato field which had been in potatoes for several years and which had a moderate infestation of the meadow nematode (Pratylenchus penetrans).

The field had been plowed and disked in late April. Cut-seed of the Katahdin variety was planted on May 17 with a two-row potato planter which applied fertilizer in side bands in rows 34" apart.

Wet soil conditions did not permit application of treatments until May 28. The soil was removed from the planted rows in a manner which

1Agronomist, Storrs Agricultural Experiment Station, The University of Connecticut, Storrs, Connecticut. Accepted for publication June 7, 1970.

2Plant Pathologist, Department of Plant Pathology and Botany, The Connecticut Agricultural Experiment Station, New Haven, Connecticut.

22 AMERICAN POTATO JOURN'AL [Vol. 48

would not disturb the fertilizer bands. The cut-seed, some of which had sprouts ~ - ~ " long and some roots, were reset with the eyes up at 9" spacing. The check plots were treated in the same manner.

Aldicarb and carbofuran were hand-applied at 3 lbs active per acre in 10~'o granular formulations. A comparison of nematode control was made between side band placement and placement in a band over the seed-pieces.

Plots 2 rows wide and 15 feet long were used. Treatments were repli- cated twice; a check plot adjoined each treatment plot. Placement of the materials in the row was compared. In one row of each treated plot, the material was hand-placed in side bands 2-3 inches from, and on both sides of, and level with the lower plane of the seed-piece. In the second row of each treated plot, the seed-pieces were covered with ~ inch of soil and the materials were applied by hand in a band 4-5 inches wide inch above the seed. The seed was then covered with 2 inches of soil. l .ater the rows were cultivated and ridged in the usual commercial method.

Soil and root samples were obtained from the middle of the rows, 3 to 6 inches below the top of the ridge, on July 21 and October 2 to determine the number of parasitic nematodes in the soil and in the potato roots. A soil core sampling tube 1" in diameter was used in obtaining the soil anti root samples. About one pound of soil was obtained from each replicate by combining several cores. The roots were separated from these core samples. Samples from each replicate were analyzed separately.

Nematodes were removed from 100 grams of soil by a modification described by Miller (2) , of the flotation-centrifugation method of Caveness and Jensen (1) . Nematodes from each plot were counted separately. Roots 1 mm or less in diameter were washed and stained in acid fuschin for 30 minutes. Meadow or root lesion nematodes were counted in 6 cm of potato roots from each plot.

Soil and root samples were also obtained from Di-Syston-treated rows which were adjacent to and on either side of the experimental area. I)i-Syston had been applied with a granular applicator and placed with the fertilizer at planting on 5/17, in bands 2-3" each side of the seed- piece.

Insects on all plots were adequately controlled by an effective spray program including the use of parathion and Meta-Systox-R.

Yields were obtained as indicated in Table 2.

1-~ESULTS

In samples of soil obtained from the middle of the row, 3 to 6 inches below the row ridge on July 21, two months after planting, the population of nematodes in the soil and in potato roots from rows treated with either systemic at both placements were markedly lower than in untreated plots (Table 1).

Potato plants on treated plots were strikingly larger than those on untreated plots. During the dry weather in late August, vines on treated plots were greener than those on untreated plots. Vines deteriorated in earl), September in untreated plots while foliage was still green in treated plots (Fig. 1). Aphids were not noticeable in any of the plots.

1971] H A W K I N S A N D MILLER: MEADOW NEMATODE CONfFROL 23

TABLE 1 . - - E f f e c t of granular systemic insecticides on m e a d o w nematodes (Praty lenchus penetrans) in soil and potato roots - - Farm H ~ 1968.

Active Nematodes in Nematodes in 100 ingredient 6 cm roots gm soil in row 4

Treatment lbs /A Placement 7/21 7/21 10/2

None 791 31 76 Furadan (10% G) 3 Sidebands 22 6 101

Over seed 03 1 114 Temik (10% G) 3 Sidebands 23 2 16

Over seed 13 1 8

Di-Syston5 2.2 Sidebands 213 14 90

1Average 8 rows (4 plots x 2 rows) , one count per untreated row. 22 plots, 2 counts each. 32 plots x 3 counts. 4Average of 4 counts. Soil samples (1 inch cores) from middle of row 3-6" below top of row ridge.

5Di-Syston, applied with granular applicator, placed with fertilizer at planting 5/17, in bands 2-3" each side of seed piece. The Di-Syston-treated rows were adjacent to and on either side of plot area.

TABLE 2 . - -E f f ec t of source and placement of gramdar systemic insecticides on yield of Katahdin potatoes as a result of nematode control I - -

Farm H - - Connecticut 1968.

Treatment Total yield 2 Over 1 ~ "2 Active Increase Increase Ibs /A Placement cwt /A cwt /A cwt/A, c w t / A

None 0 239 199 Furadan 10 G 3 Sidebands 314 75 259 60 Furadan 10 G 3 Over seed 261 22 213 14

None 0 282 246 Temik 10 G 3 Sidebands 394 112 366 120 Temik 10 G 3 Over seed 362 80 330 84

Average 0 26l 3 223z Di-Syston 4 2.2 Sidebands 2975 36 2405 17

lInsects on all plots were adequately controlled by effective spray program. 2Average of 2 untreated plots each 2 rows x 15 feet; others average of 2 split plots. 3Average of 4 untreated plots, 2 rows x 15 feet. 4Di-Syston placed with fertilizer at time of machine planting 5/17, in bands 2-3" each side of seed piece. Rows adjacent to and on either side of plot area.

5yield, average of 8 single rows 15 ft. long, bordering other plots.

24 AMERICAN POTATO JOURN~AL [Vol. 48

FIo. 1.--Plants deteroirated early on untreated plot on left (0). Solid plant cover in plot on right treated with Temik at 3~#/Aere at planting. Picture 8/29/69

FI6. 2.--Dead and defoliated plants in the untreated plot (2 rows in left {oreground). Considerable green foliage (50%) on plot treated wiwth Temik at 3#/Acre in row

at planting (2 rows in right foreground). Picture 9/16/68.

All plots had received adequate insect control by spraying. The field was irrigated on August 29, the first water since rain on August 9.

Aldiearb was more effective in controlling nematodes late into the growing season than carbofuran, as indicated in soil samples taken on October 2 (Table I ) . Miller and Kring (3) also found that aIdicarb controlled P. penetrans for a longer period than carbofuran.

Aldicarb-treated potatoes lived longer and produced a greater increase in yield over adjoining untreated potatoes than did potatoes treated with carbofuran, Table 2, Fig. 2. Yield improvement from either chemieat was

1971] HAWKINS AND MILLER: MEADOW NEMATODE CONTROL 25

g rea te r when placenient was in side bands than when placed in a band over the shallow covered seed potatoes.

Nematode popula t ions in soil samples and roots f rom rows ad jacen t to and on ei ther side of the plot a rea which bad received 10% g ranu la r disulfoton at 2.2 lbs per acre at p lant ing were lower than f rom un t rea te td rows but considerably grea te r than in the aldicarb- and ea rbofu ran- t r ea ted rows, Table 1.

ACKNOWI.EI~MENT

The assis tance and cooperat ion of E d w a r d J. and Ra lph J. Hast i l lo , Rockvil le , Connect icut in conduct ing this test on thei r fa rm is gra teful ly acknowledged.

LITERATURE CITED

1. Caveness, F. E. and H. J. Jensen. 1955. Modification of centrifugal-flotation technique for isolation and concentration of nematodes and their eggs from soil and plant tissue. Proc. Helm. Soe. Wash. 22: 87-89.

2. Miller, P. M. 1957. A method for the quick separation of nematodes from soil samples. P1. Disease Reptr. 41 : 194.

3. Miller, P. M. and J. B. Kring. 1970. Reduction of nematode and insect damage to potatoes by band application of systemic insecticides and soil fumigation. J. of Eco. Entomol. 63 : 186-189.