Pre-transplant herbicides for weed control in irrigated onion (Allium cepa L.) in northern Nigeria

Field trials were conducted at Samaru in the northern Guinea and at Bakuta and Kadawa in the Sudan Savanna ecological zones of Nigeria to identify suitable herbicides for weed control in irrigated onion. The herbicides tested were chlorthal-dimethyl, fluorodifen and oxadiazon. In the trials each herbicide treatment was compared with an identical treatment which received supplementary hand-weeding. The results of these experiments show that oxadiazon at 1·0–2·0 kg a.i./ha, with or without supplementary hoe-weeding at 6 weeks after transplanting, combined effective weed control with high bulb yields in irrigated dry season onions. While fluorodifen at 1·5 kg a.i./ha followed by supplementary hoe-weeding may be effective at sites with low weed infestation, a higher rate (3·0 kg/ha) may be desirable at sites with a higher broad-leaved weed infestation. Chlorthaldimethyl at 10·0 kg a.i./ha effectively controlled weeds at all the sites and gave high onion yields at sites with 6–12% clay; the selectivity was, however, lower at Bakura with very light soil. Uncontrolled weed growth caused 49–86% reduction in the bulb yields compared with the best herbicide treatments.     

Use of UV reflective mulch to delay the colonization and reduce the severity of Bemisia argentifolii (Homoptera: Aleyrodidae) infestations in cucurbits

Effectiveness of UV reflective plastic mulch for the management of silverleaf whitefly (Bemisia argentifolii Bellows and Perring) was evaluated in selected cucurbits. The reflective mulch repelled silverleaf whitefly adults in pumpkin (Cucurbita maxima Duchesne), cucumber (Cucumis sativus L.) and zucchini squash (Cucurbita pepo L.). Reduced colonization by B. argentifolii adults resulted in reduced populations of nymphs and a delay and reduction in the incidence of silverleaf in pumpkin and zucchini squash. Reflective mulch was as effective in reducing nymphal B. argentifolii populations as was a pre-plant soil application of imidacloprid. Zucchini squash, pumpkin and cucumber yields were significantly higher in plants grown over reflective mulch than in those grown over unmulched soil. Zucchini squash yields from plants grown over reflective mulch also were higher than from plants grown in plots receiving a pre-plant application of imidacloprid. This study confirmed that UV reflective plastic mulch can be used to manage B. argentifolii and the mulches give protection equal to that provided by imidacloprid.     

Integration of soil-applied herbicides at the reduced rates with physical control for weed management in fennel (Foeniculum vulgare Mill.)

Fennel has been widely used in traditional medicine for their antimicrobial effects. Since fennel is long duration crop and have slow initial growth, it protection from weed is essential. Experiments were conducted for two consecutive seasons to evaluate the efficacy of soil-applied herbicides at the reduced rates in combination with physical control for weed management and optimizing the yield of fennel. Treatments were type of herbicide (trifluralin and pendimethalin), application dose (recommend dose (R), 75% R, 50% R, and 0% R) and physical weed control (none, one hand-weeding at 50 day after planting (DAP), wheat straw mulch). Weed-free control treatment was also included in each year. The results showed that the use of soil-applied herbicides resulted in reduced weed biomass but did not provide season long weed control without an additional physical control. In both seasons, pendimethalin provided better weeds control than trifluralin. Reduced herbicide rates were found to be more effective when herbicides application followed by hand-weeding than when were used alone or combined with mulch. Experimental results also showed that one time increasing in herbicide rates increased seed yield by 17.5 and 7.5% in 2012 and 16.5 and 6.3% in 2013, when one hand-weeding and mulching were used as supplemental control, respectively. Overall, the 75% of the labeled recommended rate of herbicides followed by one hand-weeding at 50 DAP produced consistently high yields and less weed biomass, reflecting both superior weed control and crop safety.     

Effect of herbicides and annual weeds on the yield and seed quality of lathyrus (Lathyrus sativus L.)

Field research conducted over six location years has indicated that lathyrus (Lathyrus sativus L.) is a poor competitor with annual weed species. Failure to control annual weeds reduced lathyrus seed yields by 54–95%, depending on the weed species present and their density. Weed competition also reduced thousand-seed weight. Preplant soil-incorporated applications of trifluralin and postemergence applications of sethoxydim controlled wild oat (Avena fatua L.) and green foxtail (Setaria viridis (L.) Beav.). Trifluralin failed to control wild mustard (Sinapis arvensis L.), an important broad-leaved weed in western Canada, but this weed was controlled by both preplant soil-incorporated and postemergence applications of metribuzin. Lathyrus exhibited excellent tolerance to these herbicides, which are currently registered for use on high-acreage crops in Canada.     

Herbicide effect on growth and seed production of Lolium multiflorum in Atlantic Canada

Lolium multiflorum Lam. (annual ryegrass) is used extensively as a forage crop and seed is produced in several areas worldwide. Seed production has been shown to be commercially possible in Atlantic Canada but improved weed control is needed. Studies were conducted in two provinces (Prince Edward Island and New Brunswick) to determine the effects of the herbicides bentazon, bromoxynil/MCPA, dicamba/MCPA, thifensulfuron/tribenuron, 2,4-D and MCPA on weed control, L. multiflorum growth, seed yields and seed germination in 1998 and 1999. The herbicides MCPA, dicamba/MCPA and bromoxynil/MCPA as evaluated in these experiments provided acceptable control of the broad-leaved weeds present and had no effect on seed yield or seed germination. Although the thifensulfuron/tribenuron caused early foliar injury, the plants recovered and it provided excellent weed control. None of the herbicides affected seed germination. MCPA, dicamba/MCPA and bromoxynil/MCPA could be used to provide control of broad-leaved weeds and thifensulfuron/tribenuron could be used if growers were willing to accept some early injury and possible yield loss to obtain the improved weed control.     

Soil-applied herbicide use in wide- and narrow-row glyphosate-resistant soybean (Glycine max)

A field study was conducted in 2001 and 2002 at Blackville, SC, to compare the effectiveness of soil-applied herbicide programmes followed by glyphosate with sequential glyphosate applications in 19- and 97-cm row soybean. Treatments included pre-emergence applications of flumetsulam, chlorimuron plus sulfentrazone, metribuzin, or flumioxazin all applied with S-metolachlor with a subsequent application of glyphosate applied 5 wk after soybean planting (WAP). Additional treatments included sequential applications of glyphosate at 3 and 5 WAP and a non-treated control. Weed control was comparable in wide and narrow rows, and soil-applied herbicides were similar to sequential glyphosate applications in either row width. Amaranthus palmeri S. Wats., Digitaria sanguinalis (L.) Scop., and Cyperus rotundus L. control with all herbicides was 98–100%. All herbicide programmes provided at least 92% Ipomoea hederacea var. integriuscula Gray and I. lacunosa L. control. S-metolachlor plus flumetsulam followed by glyphosate provided 99% Senna obtusifolia (L.) Irwin and Barneby control, which was superior to the 88% and 90% obtained with chlorimuron plus sulfentrazone and metribuzin programmes, respectively. Flumioxazin and sulfentrazone caused up to 12% soybean injury. In 2001, soybean yields and gross profit margins were similar for soil-applied programmes followed by glyphosate and sequential glyphosate applications in wide and narrow rows. Conversely, soybean yields and profit margins in 2002 averaged across soil-applied programs were 380 kg/ha and $50/ha superior to sequential glyphosate applications in wide rows, but were similar in narrow rows. This research indicates a highly efficacious soil-applied herbicide program followed by glyphosate provides similar weed control to sequential glyphosate applications in wide- and narrow-row soybean; however, a soil-applied herbicide programme followed by glyphosate may improve yields and returns of wide-row soybean over sequential glyphosate applications alone.     

Reflective mulches for management of aphids and aphid-borne virus diseases in late-season cantaloupe (Cucumis melo L. var. cantalupensis)

A complex of aphids and several mosaic virus diseases can cause major losses in cucurbitaceous crops grown in the inland valleys of California. Three field experiments were conducted to test and compare the effectiveness of reflective polyethylene and biodegradable, synthetic latex spray mulches for management of aphids and aphid-borne virus diseases of late-season cantaloupe (Cucumis melo L. var. cantalupensis cv. Primo) in the San Joaquin Valley. Beneficial responses were obtained from the reflective mulches, under conditions of high aphid populations and virus inoculum potential, during each of the experiments. Aphid numbers on leaves of plants growing over mulches were consistently lower than on those growing over bare soil. Onset of symptoms of cucumber mosaic cucumovirus, and watermelon mosaic and zucchini yellow mosaic potyviruses, were delayed 3–6 weeks in plants growing over the mulches, which was critical for initiation of normal flowering and fruiting. High virus disease incidence (100% incidence of foliar symptoms) reduced cumulative, marketable melon yields (number of fruit, fresh weight, and size) in the control plots to near zero in two of the three experiments. In each of the experiments, polyethylene or spray mulch treatments which completely covered each planting bed provided at least 9.5- and 2.5-fold increases in marketable yield, respectively. In the first two experiments, reflective mulches would have provided the difference between salable crops and total crop loss. Partial bed coverage with spray mulch, and alternate row applications of polyethylene film mulches, were less effective than complete coverage of every planted row.     

Efficacy of insecticides against major insect pests of potatoes in hot climates of Peru

Soil-incorporated and foliar-applied insecticides, alone and in combination, were tested in two different tropical sites of Peru. At San Ramon (altitude 800 m) major pests during the wet season were Diabrotica spp. and Myzus persicae. Soil-incorporated insecticides gave protection against Diabrotica but not M. persicae, and yields were significantly lower with these compared with the foliar-applied insecticide, carbofuran. Mean yield was inversely and significantly correlated with mean number of Diabrotica individuals per plant (r=0·989; 0·01 <P<0·05). The foliar-applied insecticide, season, major pests were Phthorimaea operculella, M. persicae and Feltia spp. Mean yield was inversely correlated with mean number of larval mines by P. operculella on foliage (r=0·976;0·02 <P<0·05). The foliar-applied insecticide methomyl, reduced pest damage and increased yields significantly. The major pests during the dry season at Yurimagus (altitude 180m) were Diabrotica spp. Foliar application of carbaryl alone, or in combination with soil-incorporated insecticides, was equally effective in reducing damage and yield loss. An inverse significant correlation (r=0·985; 0·01<P<0·02) for yield vs. damage from Diabrotica spp. was observed.     

Broadleaved weed control in wide-row soybean (Glycine max) using conventional and glyphosate herbicide programmes

A field study was conducted in 2001 and 2002 at Blackville, SC, to evaluate broadleaved weed control and economics of conventional and glyphosate-containing herbicide programmes in glyphosate-resistant soybean planted in 97-cm-wide rows. Treatments included chlorimuron plus sulfentrazone or chlorimuron plus metribuzin applied pre-emergence followed by post-emergence applications of lactofen or glyphosate 4 wk after soybean emergence (WAE). Other treatments were glyphosate applied 4 WAE, sequential applications of low dose glyphosate applied 2 and 4 WAE, and a non-treated control. Pre-emergence herbicides followed by glyphosate, controlled Ipomoea lacunosa L. 8 WAE. I. hederacea var. integriuscula Gray control with pre-emergence herbicides followed by glyphosate was 100% with similar control from chlorimuron plus sulfentrazone followed by lactofen, whereas control following the single glyphosate application was 84%. Amaranthus palmeri S. Wats. control 9 WAE was 100% following single or sequential glyphosate applications, while control ranged from 76% to 96% with pre-emergence herbicides followed by lactofen. However, early season weed interference when a single application of glyphosate was delayed until 4 WAE reduced soybean yields an average of 389 kg/ha compared to pre-emergence herbicides followed by glyphosate. Based on mean contrasts, pre-emergence herbicides followed by glyphosate had greater gross profit margins than a single glyphosate application alone, but were similar to sequential glyphosate applications. Gross profit margins from pre-emergence herbicides followed by lactofen were not different from glyphosate alone.     

江苏“水稻-小龙虾”综合种养稻田杂草群落及其防控技术调查：以12个基地为例

为揭示江苏“水稻-小龙虾”综合种养稻田杂草群落结构和农户杂草防控措施现状,对灌南、盐都、盱眙、高邮、广陵、溧阳、常熟等7个地方12个稻虾综合种养基地开展田间调查和农户访谈。结果表明,在120块稻虾田内共记录到25种杂草;稻虾轮作田禾本科杂草和千金子的优势度显著高于稻虾共生田。稻虾轮作稻田杂草以稗属杂草、杂草稻、千金子、李氏禾、异型莎草、水苋菜属杂草、鸭舌草为主;稻虾共生稻田杂草以杂草稻、稗属杂草、千金子、异型莎草为主。除有机栽培模式外,稻虾轮作稻田控草方式为“土壤处理+茎叶处理+人工拔除”,稻田杂草防控总用药和人工成本平均1 863.75元/hm²。稻虾共生稻田控草技术主要为“水层控草+龙虾控草+人工拔除”,部分稻田使用丙草胺、苄嘧磺隆等土壤处理除草剂,稻田杂草防控总成本平均907.50元/hm²。     

Chemical control of weeds in transplanted tomatoes in Saudi Arabia

The herbicides metobromuron, diphenamid and dinitramine were tested either singly or in combination with dalapon for the control of weed species in transplanted tomato crops in Saudi Arabia, during 1979 and 1980. All herbicides were effective in controlling Chenopodium murale L., the primary broad-leaved weed in the area. However, they were less effective against other broad-leaved weed species and, even in combination with dalapon, failed to reduce populations of grass weeds. Tomato seedlings showed various degrees of injury: dinitramine was the most phytotoxic herbicide, followed by metobromuron and diphenamid. No toxicity was observed for dalapon. Diphenamid was the most promising herbicide for controlling weeds and producing significantly higher yields of tomatoes.     

Effect of mulch on soil temperature,moisture, weed infestation and yield of groundnut in northern Vietnam

Groundnut (Arachis hypogaea L.) is one of the chief foreign exchange earning crops for Vietnam. However, owing to lack of appropriate management practices, the production and the area under cultivation of groundnut have remained low. Mulches increase the soil temperature, retard the loss of soil moisture, and check the weed growth, which are the key factors contributing to the production of groundnut. On-farm trials were conducted in northern Vietnam to study the impact of mulch treatments and explore economically feasible and eco-friendly mulching options. The effect of three mulching materials (polythene, rice straw and chemical) on weed infestation, soil temperature, soil moisture and pod yield were studied. Polythene and straw mulch were effective in suppressing the weed infestation. Different mulching materials showed different effects on soil temperature. Polythene mulch increased the soil temperature by about 6 °C at 5 cm depth and by 4 °C at 10 cm depth. Mulches prevent soil water evaporation retaining soil moisture. Groundnut plants in polythene and straw mulched plots were generally tall, vigorous and reached early flowering. Use of straw as mulch provides an attractive and an environment friendly option in Vietnam, as it is one of the largest rice growing countries with the least use of rice straw. Besides, it recycles plant nutrients effectively.     

Assessment of avoidable losses and economic injury levels for the sorghum head bug, Calocoris angustatus Leth. (Hemiptera:Miridae) in India

Avoidable losses and economic injury levels (EILs) were computed for the sorghum head bug, Calocoris angustatus Leth., on three cultivars during three rainy seasons (1985–1987) at ICRISAT. Grain yield in plots protected with 2–5 insecticide sprays (carbaryl at 500 g a.i./ha) between the half-anthesis and the dough stage was significantly higher than in untreated plots, with cost-benefit ratios > 1. Plots that were not protected at half-anthesis and/or complete-anthesis, and at milk and dough stages, suffered a significant loss in yield. Bug damage spoiled the grain quality in terms of germination, 1000-grain mass, grain hardness and percentage floaters. Three to four sprays between complete-anthesis and the dough stage prevented a significant reduction in grain quality. Head bug density at half-anthesis, complete-anthesis, milk and dough stages was significantly and negatively associated with grain yield. Bug density at different stages explained 43–94% of the variance in yield. Direct effects of bug numbers at the milk stage and the indirect effects of head bug density at other stages through the milk stage contributed towards maximum reduction in yield. Maximum avoidable losses were recorded in cultivar ICSV 1 (88·6%), followed by CSH 1 (69·9%), and CSH 5 (53·9% in 1986 and 55·0% in 1987). Loss in grain yield/ha due to one insect/panicle at half-anthesis and that based on natural increase, were 548 and 232 kg in CSH 5 during 1986 and 1987, respectively, 251 kg in ICSV 1, and 77 kg in CSH 1. EILs based on a cost-benefit ratio of 1:1 ranged from 1·3–1·4 insects/panicle for CSH 1, 0·4 for ICSV 1, and 0·4–0·6 and 0·2–0·4 for CSH 5 during 1986 and 1987, respectively. Simple cost estimates for insecticide sprays and the resultant saving in grain yield are a useful tool for decision-making in pest management.     

The Effect of Natural Mulches on Crop Performance, Weed Suppression and Biochemical Constituents of Catnip and St. John's Wort

Because of expanding markets for high-value niche crops, opportunities have increased for the production of medicinal herbs in the USA. An experiment was conducted in 2001 and 2002 near Gilbert, IA, to study crop performance, weed suppression, and environmental conditions associated with the use of several organic mulches in the production of two herbs, catnip (Nepeta cataria L.) and St. John's wort (Hypericum perforatum L. 'Helos'). Treatments were arranged in a completely randomized design and included a positive (hand-weeded) control, a negative (nonweeded) control, oat straw, a flax straw mat, and a nonwoven wool mat. Catnip plant height was significantly greater in the oat straw than the other treatments at 4 wk through 6 wk in 2001; at 4 to 8 wk in 2002, catnip plant height and width was significantly lower in the negative control compared with the other treatments. Catnip yield was significantly higher in the flax straw mat than all other treatments in 2001. In 2002, St. John's wort yields were not statistically different in any treatments. All weed management treatments had significantly fewer weeds than the non-weeded rows in 2002. Total weed density comparisons in each crop from 2 yr showed fewer weeds present in the flax straw and wool mat treatments compared with positive control plots. There was no significant weed management treatment effect on the concentration of the target compounds, nepetalactone in catnip and pseudohypericin-hypericin in St. John's wort, although there was a trend toward higher concentrations in the flax straw treatment.     

Methyl bromide alternatives for weed and soilborne disease management in tomato (Lycopersicon esculentum)

Two field trials were conducted to examine the efficacy of methyl bromide (MBr) alternatives in the control of Cyperus rotundus L. (purple nutsedge) and Fusarium oxysporum Schlecht. f.sp. lycopersici (Sacc.) Snyder & Hansen (Fusarium wilt) in fresh market tomato (Lycopersicon esculentum Mill.). Various treatments compared combinations of soil fumigants and herbicides based on methyl bromide, chloropicrin, 1,3-dichloropropene, metam sodium, dazomet, and pebulate. The data show that consistently 1,3-dichloropropene plus chloropicrin at both doses in combination with the herbicide pebulate can be considered alternatives to methyl bromide in fresh market tomato. These treatments had excellent purple nutsedge and Fusarium wilt control, and marketable tomato yields were similar to that for methyl bromide plus chloropicrin.     

The impact of toxaphene applied as a post-emergence herbicide for control of sicklepod, Cassia obtusifolia L., on arthropods associated with soybean

The impact on arthropod populations of toxaphene (camphechlor) used as a herbicide was compared with cultivation and pre-emergence herbicide usage for control of sicklepod, Cassia obtusifolia L., in soybean. Soybean yields and weed control were also evaluated. Pest resurgence due to toxaphene was found to be limited, but significantly more soybean plants had main stems girdled due to the threecornered alfalfa hopper, Spissistilus festinus (Say), than those plants where toxaphene had not been applied. Both toxaphene usage and cultivation reduced early season predator abundance significantly compared with soybean where weeds were not controlled. However, the greater abundance of predators in soybeans with weeds appeared to be attributable to the increase in habitat diversity provided by the weeds and soybeans and not to a reduction in predator numbers caused by toxaphene in the treated plots. Neither soybean yields, nor the degree of sicklepod control, differed significantly between toxaphene usage and cultivation. Permethrin usage significantly reduced both pest and predator abundance in soybean.     

Broadening weed control with imazamethabenz combinations

Broad-spectrum weed control by use of imazamethabenz (AC 222 293) in herbicide combinations was investigated in the greenhouse. Imazamethabenz at rates ranging from 0·1 to 0·4 kg a.i./ha effectively controlled wild oats (Avena fatua L.). Additional control of redroot pigweed (Amaranthus retroflexus L.) was achieved when imazamethabenz, plus octoxynol surfactant, was applied in combination with MCPA (amine or ester) or commercial MCPA mixtures (bromoxynil/MCPA and cyanazine/MCPA). Only inclusion of propanil/MCPA in the combination reduced wild-oat control by imazamethabenz at the lower rate (0·1 kg/ha). Control of green foxtail (Setaria viridis (L.) Beauv.) was also obtained by use of fenoxaprop-ethyl in combination with imazamethabenz (plus octoxynol). Three-way mixtures of imazamethabenz (or plus octoxynol), MCPA alone or mixture, and fenoxaprop-ethyl may provide practical control of grass and broad-leaved weeds in the field.     

Effects of straw mulch on mungbean yield in rice fields with strongly compacted soils

In rice-based lowland areas in the Mekong region, the lack of full irrigation water availability for post-rice legume crops and the poor soil physical and chemical conditions are major constraints for development of sound rice/legume double cropping system. In order to improve legume productivity, use of rice straw mulch and various crop establishment methods were examined in two series of mungbean experiments in Cambodia where soils were coarse and strongly compacted. In one set of experiments conducted at four locations in the first year the effect of straw mulch, planting method (manual vs seed drill) and tillage method (conventional vs no-till) was examined. Another set of experiments were conducted in the second year at three locations with four levels of mulch under two planting densities. On average in year 1, mulching of rice straw at 1.5 t/ha increased mungbean crop establishment from 72 to 83%, reduced weed biomass from 164 to 123 kg/ha and increased yield from 228 to 332 kg/ha. Mulch was effective in conserving soil moisture, and even at maturity the mulched area had on average 1% higher soil moisture content. The amount of mulch between 1 and 2 t/ha did not show consistent effects in year 2, partly because some mulch treatments resulted in excessive soil moisture content and were not effective. Rice straw mulch had a significant effect on mungbean yield in 6 out of the 7 experiments conducted in two years, and mean yield increase was 35%. This yield advantage was attributed to better crop establishment, improved growth and reduced weed pressure, but in some cases only one or two of these factors were effective. On the other hand, planting method, tillage method and planting density had only small effects on mungbean yield in most experiments. Only in one location out of four tested, the no-till treatment produced significantly higher yield than the conventional method. Seed drill produced similar mungbean establishment and grain yield to the manual planting suggesting that the planter can be used to save the labour cost which is increasing rapidly in the Mekong region. Maximum root depth varied little with mulch or planting density, and was shallow (<20 cm) in all three locations where this character was determined. It is concluded that while rice straw mulch increased yield of mungbean following rice, the inability of mungbean roots to penetrate the hard pan is a major constraint for development of a sound rice/mungbean cropping system in the lowlands with compacted soils.     

Selectivity and weed control efficacy of pre- and post-emergence applications of clomazone in Southern Brazil

During the 2006/07 and 2008/09 growing seasons in Southern Brazil, we evaluated crop selectivity and weed control efficacy of clomazone on rice when applied alone or in a mixture with other pre- and post-emergence herbicides (BRS Querência variety). All herbicide treatments caused some degree of rice injury during both years; however, in no case was the injury still visible 21 days after application. Rice injuries were observed when application rates exceeded the recommended dose, and particularly when the herbicide was applied pre-emergence. Density reduction and panicle sterility served as measures of rice injury. Echinochloa crus-galli was the primary weed; it reduced rice yields by approximately 50% compared treated plots. In both growing seasons, clomazone herbicide (400 g ai ha⁻¹) controlled the weed 87.0%–99.6%, and it provided 8.06 t ha⁻¹ to 9.44 t ha⁻¹ of rice yield.     

Development and growth of two Lesquerella species grown under different temperatures during the reproductive period

The genus Lesquerella is a promising source of hydroxy fatty acids (HFA). Several species such as Lesquerella fendleri and Lesquerella mendocina are candidate crops for arid and semi-arid cropping systems. Several reports are available on the environmental effects on growth and yield in Lesquerella, but information on the effect of temperature on plant growth and development specifically during the reproductive period in Lesquerella is limited. The objective of this work was to determine the effect of two contrasting thermal regimes after flowering on time to maturity, plant growth and biomass allocation to the different organs in L. fendleri and L. mendocina. A greenhouse experiment was conducted with plants grown at a range of 11–23 °C during the vegetative phase. After this stage, 50% of the plants of each species remained under the same temperature regime until maturity, whereas the other 50% was transferred to another module subjected to a range of 17–31 °C until maturity. The duration of the reproductive phase was reduced by 23 days in plants of both species in the 17–31 °C treatment compared to those at 11–23 °C, although no differences were observed when the length of the reproductive phase was measured in thermal-time units. Total plant biomass for both species was 20% greater in the 11–23 °C treatment. In L. fendleri, this increment occurred due to more vegetative shoot biomass, whereas in L. mendocina it was associated with greater reproductive and root biomass. No changes in biomass allocation were produced by temperature in L. fendleri, while in L. mendocina the lower temperature regime increased allocation to the reproductive organs, at the expense of a lower allocation to vegetative shoot. These results could be used to predict the specific temperature effects after flowering on yield under field conditions, and suggest that L. mendocina might be a promising perennial alternative for cooler sites.