Evaluation of new herbicides for capsicums and chillies
Evaluation of new herbicides for capsicums and chillies
Serve-Ag Research, PO Box 690, Devonport, Tasmania 7310, Australia
Summary Effective weed management strategies are
300 kPa. In all data presented here, oxadiargyl,
limited for capsicum and chilli producers. Current weed
pendimethalin and clomazone were applied pre
management practices include the use of plastic mulch,
transplant, within two days of transplanting. Plot sizes
selective grass herbicides, handweeding or tillage.
were between 10 and 30 m2. Assessments were
There are currently no herbicides registered for conducted as whole plot subjective ratings using the broadleaf weed control in capsicums or chillies.
European Weed Research System (EWRS) scales for
Potential new herbicides were screened and weed control efficacy (1 = total weed control, 9 = no
efficacy, crop safety and residue data was generated. A
effect on weeds) and crop tolerance (1 = healthy plant, 9
total of 13 trials were conducted over three seasons
= crop killed) (Puntener, 1981). Weed density counts
throughout major Australian production regions. The
were conducted using randomly placed quadrats and
most effective herbicides identified from this work were
results presented as percent control compared to the
pendimethalin, clomazone and oxadiargyl, which all
untreated control. Crop yield measurements were
gave best results when applied pre crop transplanting. conducted by harvesting 10 plants per plot and All three products provided effective pre emergent
classifying fruit into marketable and non-marketable
control of a range of common broadleaf and grass weeds
categories, based on factors such as size and colour.
Clomazone, oxadiargyl and pendimethalin applied at
double the proposed use rates, on soils with very low
levels of organic carbon and clay, did not cause any
crop phytotoxicity. Yield and quality of capsicum and
chillies was also not affected by these herbicides.
Keywords capsicum, chilli, oxadiargyl, pendimethalin,
Capsicums and chillies are grown from transplants
commercially throughout Australia, although most of
the production is in Queensland. Effective weed
management strategies are limited for capsicum and
chilli producers. Current weed management practices
include the use of plastic mulch, selective grass
herbicides, handweeding or tillage. There are currently
no herbicides registered for broadleaf weed control in
capsicums or chillies. The development of effective
broadleaf weed herbicides, to be used as part of an
integrated weed management program in capsicum and
chilli production in Australia, is essential.
A total of 13 replicated small plot trials were conducted
over three seasons throughout major Australian
production regions. Trials were conducted in North West Tasmania, Perth (Western Australia), Atherton (North Queensland) and Bowen (North Queensland). Small plot trials were sprayed with flat fan nozzles, generally applying water rates of between 200 and 300 litres/ha at an application pressure of between 200 and
(crowsfoot grass) control but was not as effective as
pendimethalin and clomazone on these weeds (Table 4).
Oxadiargyl at 400 g a.i. ha-1 was generally more
effective than clomazone at 480 g a.i. ha-1 and
pendimethalin at 990 g a.i. ha-1 for controlling broadleaf
weeds (Tables 5 & 6), although all products provided
weeds AMACH Amaranthus hybridus (green amaranth),
CHEAL Chenopodium album (fat hen) and POROL
9.8 Portulaca oleracea (pigweed).
Crop safety The three herbicides oxadiargyl,
pendimethalin and clomazone, applied pre transplant
showed high crop safety over a number of sites with
average EWRS crop ratings of 1.1, 1.4 and 1.1
respectively (Table 2). Yield data from a trial in Bowen
showed these herbicides had no affect on marketable
yield of either capsicum (cv Blister) (Table 2) or Chilli
(cv. Warlock) (Table 3). This trial was conducted on a
light textured soil with a cation exchange capacity of 5.9
Sulfentrazone, flumioxazine, carfentrazone, oxyfluorfen,
metribuzin, isoxaflutole and imazamox were also weeds SOLNI (Solanum nigrum, black nightshade), screened, but they were not further evaluated due to
SONOL (Sonchus oleraceus, sow thistle) and TRBTE
weeds ELEIN (Eleusine indica, crowsfoot grass) and
DIGAD (Digitaria ciliaris, summer grass).
Herbicide residues in fruit Analysis of clomazone
and pendimethalin residues in capsicum fruit showed
that when applied pre transplant, these herbicides were
Weed efficacy The three herbicides pendimethalin,
not detected at a limit of quantification of 0.01 mg/kg at
clomazone and oxadiargyl all showed activity on two sites. common grass and broadleaf weeds in capsicum and
chilli crops. Both clomazone at 480 g a.i./ha and
pendimethalin at 990 g a.i. ha –1 provided near complete
Trial data at 13 sites over three seasons has shown
control of Eleusine indica (crowsfoot grass) and clomazone, pendimethalin and oxadiargyl provide Digitaria ciliaris (summer grass). Oxadiargyl at 400 g
control of a number of problem weeds while being safe
a.i. ha –1 provided 91% (summer grass) and 84%
to capsicum and chilli crops. A variety tolerance trial was conducted at Bowen in North Queensland on a light
textured soil with a cation exchange capacity of 5.9 cmol kg-1. This site presented a worst case scenario for crop safety with soil applied herbicides and the herbicide rates used in this trial were approximately double those required for control of susceptible weeds. Despite this, the products showed high crop safety with no effect on marketable yield of capsicum or chilli.
Clomazone, pendimethalin and oxadiargyl can
potentially be used to manage weeds under plastic mulch, in inter-rows between plastic mulch or within rows in crops grown without plastic mulch. Effective herbicide options may even assist growers to reduce their reliance on plastic mulch in capsicum and chilli crops in some situations.
These products can not be used in commercial crops
until permits or registrations are obtained from the Australian Pesticides and Veterinary Medicines Association. The information generated from this project maybe used to support these applications.
Funding supported by National Vegetable Research & Development Levy and Commonwealth Government through Horticulture Australia Ltd. We thank all growers who kindly provided trial sites. We also thank all researchers who undertook trials as part of this project. Researchers included, Mark Sumner, Chris Monsour, Keith Lewis and David Kilpatrick.
Frost P and Hingston T (2004). Weed Management in
Capsicums and Chillies. Horticulture Australia Ltd Final Report.
Puntener W (1981). Manual for Field Trials in Plant
Protection. Second Edition. Ciba-Geigy Limited, Basle, Switzerland.
Thomson W (1997). Agricultural Chemicals Book II
Herbicides. Thomson Publications, California.
Asthma Attack We have formed our policy and procedures for Asthma through the Warrington Schools Policy, St Joseph’s Catholic Primary school have adopted this policy and we feel it would benefit both the children and our staff to adopt this policy for our own club for familiarity for al involved. Asthma maybe manifested through the fol owing symptoms: • Coughing • Tight Chest • Wheez