Dermacor X-100 Hybrid Treatment Rates for Rice Water Weevil ...

Dermacor X-100 Hybrid Treatment Rates for Rice Water Weevil Control
Block 3N
Beaumont, TX
2009
PLOT PLAN
⇐ North
I II III IV
1 5 7 6 13 2 19 4
2 4 8 2 14 1 20 3
3 1 9 3 15 5 21 2
4 2 10 4 16 6 22 5
5 6 11 5 17 3 23 1
6 3 12 1 18 4 24 6
Plot size: 7 rows, 7 inch row spacing, 18 ft long with metal barriers
Variety: XL723 (seed provided by Rice Tec)
Border plots (XL723) on east and west side of test
Note: smaller numbers in italics are plot numbers
TREATMENT DESCRIPTION, RATE AND TIMING
Treatment no. Description (fl oz/cwt seed) (lb ai/A) Timing a
1 Dermacor X-100 3.0 0.037 ST
Rate
2 Dermacor X-100 4.5 0.055 ST
3 Dermacor X-100 6.0 0.073 ST
4 Dermacor X-100 9.0 0.110 ST
5 Karate Z --- 0.03 BF
6 Untreated --- --- ---
a ST = seed treatment (30 lb/A seeding rate); BF = immediately before flood
4
M.O. Way ⋅ moway@aesrg.tamu.edu ⋅ (409)752-2741 ext.2231
Texas AgriLife Research and Extension Center at Beaumont ⋅ 1509 Aggie Dr. ⋅ Beaumont, TX 77713 ⋅ http://beaumont.tamu.edu

Dermacor X-100 Hybrid Treatment Rates for Rice Water Weevil Control
Agronomic and Cultural Information
Experimental design: randomized complete block with 6 treatments and 4 replications
Planting: Drill-planted XL723 @ 30 lb/A into League soil (pH 5.5, sand 3.2%, silt 32.4%,
clay 64.4%, and organic matter 3.8 - 4.8%) on Apr 8
Plot size = 7 rows, 7 inch row spacing, 18 ft long with metal barriers
Emergence on Apr 23
Irrigation: Flushed blocks (temporary flood for 48 hours, then drain) on Apr 8
Note: Plots were flushed as needed from emergence to permanent flood
Permanent flood (PF) on May 19
Fertilization: All fertilizer (urea) was distributed by hand.
120 lb N/A (1/3 of 170) on May 19 at PF
60 lb N/A (1/3 of 170) on Jul 2 at 5% heading
Total N = 180 lb/A
Herbicide:
Stam 80EDF @ 2.0 lb, Basagran @ 0.75 lb, Facet 75DF @ 0.25 lb and Ordram
@ 2.0 lb (AI)/A and Agri-Dex @ 1.0 pt/A with a 2-person hand-held spray
boom (13- 80015 nozzles, 50 mesh screens, 16 gpa final spray volume) on May
8 for early season weed control
Treatments: Treatment 5 (Karate Z @ 0.03 lb AI/A) applied using a hand-held, CO 2
pressurized, 3 nozzle (800067 tips with 50 mesh screens, 29 gpa) spray rig on
May 19 (before PF)
Sampling: Stand counts (3- 3 ft counts on rows 2, 4 and 6) on May 2
Rice water weevil (RWW) cores (5 cores per plot, each core 4 inches diameter, 4
inches deep, containing at least one rice plant) were collected on Jun 9 and Jun
19. Core samples were stored in a cold-room, later washed through 40 mesh
screen buckets and immature RWW counted.
Note: Prior to analysis RWW counts transformed using square root (x + 0.5)
Whitehead (WH) counts in rows 1 – 3 and 5 – 7; collected WHs for dissection (5
MRB; 0 SCB) on Jul 29
Harvest: Harvested plots on Aug 12
Size harvested plot = 7 rows, 7 inch row spacing, 18 ft long
Yields converted to lb/A and adjusted to 12% moisture
Data analysis: RWW and WH counts transformed using x + 0.5 ; yields converted to 12%
moisture; all data analyzed by ANOVA and means separated by LSD
5
M.O. Way ⋅ moway@aesrg.tamu.edu ⋅ (409)752-2741 ext.2231
Texas AgriLife Research and Extension Center at Beaumont ⋅ 1509 Aggie Dr. ⋅ Beaumont, TX 77713 ⋅ http://beaumont.tamu.edu

Dermacor X-100 Hybrid Treatment Rates for Rice Water Weevil Control
Discussion
Populations of RWW were high in untreated plots on both sample dates (Table 1). All
Dermacor X-100 treatments provided better RWW control than the Karate Z treatment on both
sample dates. Among Dermacor X-100 treatments, data show all tested rates effectively
controlled RWW; however, the lowest rate (0.037 lb ai/A) gave a slight decrease in control
compared to the higher rates. Dissection of rice plants revealed the predominant stalk borer
species in the experiment was MRB. Although WH counts in plots without Dermacor X-100
seed treatment were low (typical of hybrid varieties), all Dermacor X-100 seed treatments
significantly reduced WHs compared to Karate Z plots. All Dermacor X-100 seed treatments
produced excellent yield responses (due to a combination of RWW and stalk borer control). The
lowest rate of Dermacor X-100 produced yields similar to the highest rate (1355 and 1034 lb/A
yield advantage over the untreated in lowest and highest rates of Dermacor X-100, respectively).
Results of this experiment suggest at low seeding rates of hybrid varieties excellent control of
RWW and stalk borers can be achieved with lower than currently recommended rates of
Dermacor X-100. In fact, Dermacor X-100 at 0.037 lb ai/A, given a seeding rate of 30 lb/A,
provided good control of both RWW and stalk borers, and produced an excellent yield response.
The Karate Z treatment did not provide as good control of RWW compared to the Dermacor X-
100 treatments and did not control stalk borers. However, yield response to the Karate Z
treatment was excellent.
Table 1. Mean data for Dermacor X-100 hybrid treatment rate study. Beaumont, TX. 2009.
Rate
No. RWW b /5 cores WHs b in 6 Yield
Treatment (lb ai/A) Timing a Jun 9 Jun 19 rows (lb/A)
Dermacor X-100 0.037 ST 4 bc 6 c 0 c 9780 a
Dermacor X-100 0.055 ST 1 c 0 d 1 c 9732 a
Dermacor X-100 0.073 ST 0 c 1 d 0 c 8874 b
Dermacor X-100 0.110 ST 1 c 1 d 0 c 9459 a
Karate Z 0.03 BF 8 b 15 b 4 a 9788 a
Untreated --- --- 63 a 54 a 2 b 8425 b
a ST = seed treatment (30 lb/A seeding rate); BF = immediately before flood
b RWW = rice water weevil (larvae + pupae); WHs = whiteheads
Means in a column followed by the same letter are not significantly different (P = 0.05, ANOVA
and LSD).
6
M.O. Way ⋅ moway@aesrg.tamu.edu ⋅ (409)752-2741 ext.2231
Texas AgriLife Research and Extension Center at Beaumont ⋅ 1509 Aggie Dr. ⋅ Beaumont, TX 77713 ⋅ http://beaumont.tamu.edu