Vol. 16—1962 - NorthEastern Weed Science Society

181
CONTROLOF ANNUALWEEDSIN pOTATOES
M.F. Trevett, H.J. MUl'phy, and Robert Littlefield Y
Introdulllt
ion
This paper is a report on the effectiveness of the herbicides
listed in Table 1 on the control of annual broadleaf weeds and
annual grasses in potatoes. Comparisons were made between herbicides
applied singly, Block II,and between various combinations
of herbicides, Block· I. Com1:lination treatments were applied to.
dete~mine the likelihood of aomplementaryactibn that would either
increa.se percent total weed oontrol or lengthen the period of
effective weed oontrol. .
Procedure
Two blocks of Katahdin potatoes were planted in a sandy lQ8m
soil in late May, 1961. Block I was planted 22 May, Block II was
:planted 26 May. .Seed pieces were spaced 12 inches apart in ro~s
42 inches apart. "Planting" treatments were applied 24 May in
Block I and 29 May in Block II, two and three days after planting.
Emergence treatments were applied when about 5%of the plants had
emerged: 12 June in Block I, ahd 13 June in Bloo,k II.
Treatments were replicated six times in randomized blocks .of
single row plots paired with untreated plots. Herbicides were
applied with one pass of a small plot spraye.r at 40 pounds pressure
and 50 gallons per acre volume. Potatoeswel'e hilled three times.
The final hill was 24 inches wide at the base, 10 inches high, and
6 inches wide at the top. .
The principal broadleatweeds were: Wild Rutabaga (Brassic,
rapa Li), Red-root Pigweed (Amaranthus l'etrotlexusL.), Lambsquarters
Pigweed (ChenopodiUll1 album t.), Ragwe,ed {Ambrosia
artem1s11!gUj. L. h andsmal'tweed (POlY~OaUll! pensYlvanicum L.).
The annua! gl'asses pl'esent we.re: Barny-ar Grass· (EOhlnochloa Cl'USgatp
L.) and Foxtail (Seteria viridis L.). 'Weed counts and~
ra ngs were made- approximately twelve weeks atte.r treatments.
11 Associate Agronomists, and Technical Assistant, respectively,
Agronomy Dep8r~ent, Maine Agl'icultural Experiment Station,
Univel'sity of Maine, Orono, Maine.