Fungi Isolated from Flue-cured Tobacco at Time of Sale and After Storage

The fungi isolated from 100 samples of flue-cured tobacco from 12 markets in 2 tobacco belts comprised 11 genera, including 10 species of Aspergillus. The mean percentage per sample isolated from 62 samples of tobacco from Middle Belt markets was Alternaria, 40.6%; Aspergillus niger, 47.8%; Aspergillus repens, 38.0%; and Penicillium, 25.8%. The mean percentage per sample isolated from 38 samples of tobacco from Old Belt markets was Alternaria, 74.0%; Penicillium, 52.5%; Aspergillus repens, 38.0%; and Aspergillus ruber, 36.2%. Damaged (74 samples) and nondamaged (26 samples) stored tobacco yielded species of six genera of fungi, including eight species of Aspergillus. Species of Aspergillus and Penicillium were commonly isolated from both damaged and nondamaged tobacco, whereas species of Alternaria, Cladosporium, Fusarium, and Rhizopus were isoalted more frequently from nondamaged tobacco. The fungi that occurred in the highest population in damaged tobacco were Aspergillus repens, A. niger, A. ruber, and Penicillium species.     

Differential benefits of arbuscular mycorrhizal and ectomycorrhizal infection of Salix repens

 The functional significance of arbuscular mycorrhiza (AM) and ectomycorrhiza (EcM) for Salix repens, a dual mycorrhizal plant, was investigated over three harvest periods (12, 20 and 30 weeks). Cuttings of S. repens were collected in December (low shoot P) and March (high shoot P). Glomus mosseae (an arbuscular mycorrhizal fungus, AMF) resulted in low AM colonization (<5%), but showed large short-term (<12 weeks) effects on shoot growth and root length. Hebeloma leucosarx (an ectomycorrhizal fungus, EcMF) resulted in high EcM colonization (70%), but benefits occurred over a longer term (>12 weeks). Furthermore, G. mosseae colonization resulted in higher shoot P uptake, shoot growth, root growth and response duration for S. repens collected in December than for those collected in March, whereas with H. leucosarx and the non-mycorrhizal treatment there were no differences between cuttings collected on different dates. Low AMF colonization was effective in the short term for cuttings at both collecting dates. Low AMF colonization of S. repens occurred irrespective of the amount of AMF inoculum used. The intensities and relative amounts of AMF structures in S. repens and Trifolium repens were compared over three harvest periods (12, 20 and 30 weeks) to assess plant species effects on AM colonization patterns. Accepted: 13 October 2000     

Trap Crops and Population Management of Globodera tabacum tabacum

Tobacco, eastern black nightshade, and tomato were grown for 3 to 13 weeks to assess differences in invasion, development, and soil density of Globodera tabacum tabacum (tobacco cyst nematode) in field plots and microplots over three seasons. Tobacco cyst nematodes invaded roots of resistant and susceptible tobacco, nightshade, and tomato. Nematode development was fastest in nightshade and slowest in tomato, and few adults developed in roots of nematode-resistant tobacco. Soil populations of tobacco cyst nematodes were reduced up to 80% by destroying nightshade or susceptible tobacco grown for 3 to 6 weeks. Nematode populations were reduced up to 96% by destroying tomato or resistant tobacco grown for 3 to 6 weeks. Timing of crop destruction was less critical with tomato and resistant tobacco, as nematode populations did not increase after 13 weeks of growth. These studies demonstrate that trap cropping, through crop destruction, can significantly reduce G. t. tabacum populations.     

Changes in fungi and mycotoxins in pearl millet under controlled storage conditions

Pearl millet is increasingly being grown as a premium-value grain for the recreational wildlife and poultry industries in the southern US. We conducted three experiments to assess grain mold development in storage conditions typically encountered in the region of production. Variables included production year, temperature, relative humidity, atmosphere, and grain moisture content. In the first experiment, grain was stored for 9 weeks at 20 or 25°C and maintained at 86% or 91% relative humidity (r.h.). In the second experiment, grain was stored for 9 weeks at 20 or 25°C in either air (aerobic) or N₂ (anaerobic), and maintained at 100% r.h. In the third experiment, high-moisture grain was stored for 3 weeks at 20 or 25°C and maintained at 100% r.h. Grain was sampled at weekly intervals and plated to determine changes in fungal frequency. Fungi isolated included Fusarium chlamydosporum (19% of grain), Curvularia spp. (14%), F. semitectum (16%), Alternaria spp. (9%), Aspergillus flavus (8%), “Helminthosporium”-type spp. (6%), and F. moniliforme sensu lato (3%). Year of grain production significantly affected isolation frequency of fungi. Isolation frequencies from low-moisture grain were rarely affected by temperature, relative humidity, or atmosphere treatments, but was affected by storage duration for some fungi. Changes in isolation of toxigenic fungi occurred in high-moisture grain. Isolation frequency of F. chlamydosporum increased in grain stored at 86% and 91% r.h. Incidence of A. flavus increased in high-moisture grain treatments, particularly at 25°C. Incidence of deoxynivalenol was not affected by storage treatment. Low concentrations of nivalenol were detected in most grain incubated at 100% r.h. Zearalenone was detected only when grain moisture content was 20–22%. Aflatoxin contamination averaged 174 ng g⁻¹ over all treatments, and increased up to 798 ng g⁻¹ in high-moisture grain at stored at 25°C.     

Are carbon and nitrogen exchange between fungi and the orchid Goodyera repens affected by irradiance?

Background and Aims The green orchid Goodyera repens has been shown to transfer carbon to its mycorrhizal partner, and this flux may therefore be affected by light availability. This study aimed to test whether the C and N exchange between plant and fungus is dependent on light availability, and in addition addressed the question of whether flowering and/or fruiting individuals of G. repens compensate for changes in leaf chlorophyll concentration with changes in C and N flows from fungus to plant.Methods The natural abundances of stable isotopes of plant C and N were used to infer changes in fluxes between orchid and fungus across natural gradients of irradiance at five sites. Mycorrhizal fungi in the roots of G. repens were identified by molecular analyses. Chlorophyll concentrations in the leaves of the orchid and of reference plants were measured directly in the field.Key Results Leaf δ¹³C values of G. repens responded to changes in light availability in a similar manner to autotrophic reference plants, and different mycorrhizal fungal associations also did not affect the isotope abundance patterns of the orchid. Flowering/fruiting individuals had lower leaf total N and chlorophyll concentrations, which is most probably explained by N investments to form flowers, seeds and shoot.Conclusions The results indicate that mycorrhizal physiology is relatively fixed in G. repens, and changes in the amount and direction of C flow between plant and fungus were not observed to depend on light availability. The orchid may instead react to low-light sites through increased clonal growth. The orchid does not compensate for low leaf total N and chlorophyll concentrations by using a ¹³C- and ¹⁵N-enriched fungal source.     

Influence of arbuscular mycorrhiza on the growth and antioxidative activity in cyclamen under heat stress

The influence of the arbuscular mycorrhizal (AM) fungus, Glomus fasciculatum, on the growth, heat stress responses and the antioxidative activity in cyclamen (Cyclamen persicum Mill.) plants was studied. Cyclamen plants (inoculated or not with the AM fungus) were placed in a commercial potting media at 17–20 °C for 12 weeks in a greenhouse and subsequently subjected to two temperature conditions in a growth chamber. Initially, plants were grown at 20 °C for 4 weeks as a no heat stress (HS?) condition, followed by 30 °C for another 4 weeks as a heat stress (HS+) condition. Different morphological and physiological growth parameters were compared between G. fasciculatum-inoculated and noninoculated plants. The mycorrhizal symbiosis markedly enhanced biomass production and HS + responses in plants compared to that in the controls. A severe rate of leaf browning (80–100 %) was observed in control plants, whereas the mycorrhizal plants showed a minimum rate of leaf browning under HS + conditions. The mycorrhizal plants showed an increase activity of antioxidative enzymes such as superoxide dismutase and ascorbate peroxidase, as well as an increase in ascorbic acid and polyphenol contents. The 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity also showed a greater response in mycorrhizal plants than in the control plants under each temperature condition. The results indicate that in cyclamen plants, AM fungal colonisation alleviated heat stress damage through an increased antioxidative activity and that the mycorrhizal symbiosis strongly enhanced temperature stress tolerance which promoted plant growth and increased the host biomass under heat stress.     

Metabolic Changes in Partially Dormant Wheat Seeds during Storage

Changes in germination, seedling growth, respiration, response to applied gibberellic acid, and glucose-U-¹⁴C utilization were investigated in partially dormant wheat (Triticum aestivum L., Pa 151 × 107) seeds which were stored under various conditions for periods up to 1 year. Only seeds stored at −20 C and 12.4% moisture maintained partial dormancy, which was overcome by germinating in 10⁻³m gibberellic acid. Germination and seedling growth of seeds stored at 25 C and 15.1% moisture declined within 12 weeks and the percentage of seeds infected with storage fungi increased. Gibberellic acid produced faster growing seedlings, particularly from those seeds with partial dormancy, but did not overcome growth reduction which was caused by deterioration. Seeds kept under laboratory conditions (B), 25 C and 12.1% moisture (C), and 25 C and 15.1% moisture (D) for 12 weeks utilized 35, 55, and 80% less glucose, respectively, than those stored at −20 C and 12.4% moisture (A). Seeds stored under B and C consistently had higher germination, growth, and respiratory rates than seeds from A and D. The respiratory rate declined as deterioration advanced under D. Respiratory quotients ranged from 1.0 for seeds stored under A to 1.6 for seeds stored under D.     

Psychrophilic and Mesophilic Fungi in Fruit-Filled Pastries

Surveys of the mold flora of frozen blueberry and cherry pastries were undertaken. Molds were enumerated by preparing pour plates of the blended product and incubating the plates at 0, 5, 10, and 20 C. In this manner, the total fungal content of the product could be ascertained from the 10 and 20 C plates, and the psychrophilic fungal population was represented by those fungi which grew at 0 and 5 C. The pastry portion, or crust, of the blueberry material was sampled separately from the filling portion. Certain differences in fungal flora were apparent. Aureobasidium pullulans was the dominant fungus in crust at all temperatures of isolation. However, Penicillium thomii proved to be the most common mesophilic fungus in the filling portion, and A. pullulans was the most common psychrophile in the filling. Aspergilli were quite common in the crust, but, in general, were absent from the fruit filling. Cherry pastries had a much smaller total fungal flora than did the blueberry product. However, A. pullulans again was the most prevalent fungus in cherry pastries at all temperatures of isolation. Certain differences in fungal flora were apparent in the two fruit products. Phoma spp. were almost completely absent in blueberries, but represented the second most common fungus in cherry pastries. Blueberry filling had 440 psychrophilic fungi per gram of sample (at 0 C), blueberry crust had 65 per gram, and cherry pastries had 77 per gram.     

Collagenolytic activity in several species of deuteromycetes under various storage conditions

The ability of deuteromycetes of the genera Penicillium, Aspergillus, and Botrytis to retain collagenolytic activity was studied after both 2 and 10 years of storage on a Czapek medium under a layer of mineral oil at 4°C, as well as in silica gel granules at 20 and ?60°C. The enzymatic activity of several species, including Botrytis terrestris, Penicillium janthinellum, Penicillium chrysogenum, and Penicillium citrinum, was retained under both conditions of storage. Aspergillus repens retained enzymatic activity only if stored under a layer of mineral oil. The viability of conidia and the collagenolytic activity of Botrytis terrestris, P. janthinellum, P. chrysogenum, and Penicillium citrinum, maintained on silica gel for 10 years, depended on the storage temperature. The viability of the test strains improved after storage on a silica gel at ?60°C. A strain of Aspergillus repens lost its ability to dissolve collagen at various storage tempeatures on the silica gel. The index of lysis for three strains of Penicillium deuteromycetes (Penicillium janthinellum, Penicillium chrysogenum, and Penicillium citrinum) increased after a 10-year storage on silica gel at ?60°C.     

Regeneration of Plants from Cell Suspensions Frozen at −20, −70 and −196°C

Cell suspensions of carrot, Datura, tobacco and soybean subjected to ?20°C, ?70°C and ?196°C in the presence of a suitable cryoprotective agent, and stored for various lengths of time have been revived. After revival these cells divided to form callus masses. Direct immersion in liquid nitrogen invariably killed the cells, whereas cooling at the rate of 1 or 2°C/min, or pre-freezing briefly at ?20 and ?70°C, followed by freezing at ?196°C retained the viability. Depending on the plant species up to 70% of the cell clumps could withstand ultra-cooling. Tobacco and Datura cell suspensions were more sensitive to cold treatment than were those of carrot. Actively growing cell suspensions containing small cell-clumps revived rapidly, while filtered cell-suspensions of free cells only occasionally survived. Calli of tobacco and carrot obtained from frozen suspensions have been regenerated into plants.     

Glycated Albumin at 4 Weeks Correlates with A1C Levels at 12 Weeks and Reflects Short-Term Glucose Fluctuations

Objective: Evaluate the performance of glycated albumin (GA) monitoring by comparing it to other measures of glycemic control during intensification of antidiabetic therapy.Methods: This 12-week, prospective, multicenter study compared the diagnostic clinical performance of GA to glycated hemoglobin A1C (A1C), fructosamine corrected for albumin (FRA), fasting plasma glucose (FPG), and mean blood glucose (MBG) estimated from self-monitoring of blood glucose (SMBG) and continuous glucose monitoring (CGM) in 30 patients with suboptimally controlled type 1 or 2 diabetes.Results: Mean A1C decreased from 9.5% to 8.1%. Mean SMBG correlated closely with CGM (Pearson r = 0.783 for daily estimates and r = 0.746 for weekly estimates, P<.0001). Both GA and FRA levels significantly correlated with changes from baseline in A1C and mean weekly SMBG (P<.001). The lowest observed median GA occurred at 4 weeks, followed by a small increase and then a slight reduction, mirroring changes in overall mean SMBG values. The median A1C fell throughout the treatment period, failing to reflect short-term changes in SMBG. A ≥1% reduction in GA at 4 weeks was significantly associated with a ≥0.5% change in A1C at 12 weeks (odds ratio &lsqb;OR] = 19.0, 95% confidence interval &lsqb;CI]: 1.4, 944, P = .018).Conclusion: In patients receiving glucose-lowering therapy, changes in GA at 4 weeks were concordant with changes in A1C at 12 weeks, and both GA and FRA more accurately reflected short-term blood glucose fluctuations than A1C.Abbreviations: A1C = glycated hemoglobin A1C ARIC = Atherosclerosis Risk in Communities CGM = continuous glucose monitoring FPG = fasting plasma glucose FRA = fructosamine corrected for albumin GA = glycated albumin MBG = mean blood glucose OR = odds ratio SMBG = self-monitoring of blood glucose     

Influence of Modified Atmosphere Storage on Aflatoxin Production in High Moisture Corn

Samples of freshly harvested corn and remoistened corn were inoculated with Aspergillus flavus and stored for 4 weeks at about 27 C in air and three modified atmospheres. Aflatoxins and fat acidity were determined weekly. Corn stored in the modified atmospheres did not accumulate over 15 μg of aflatoxin B₁ per kg and 20 μg of total aflatoxins per kg. Corn from the high CO₂ treatment (61.7% CO₂, 8.7% O₂, and 29.6% N₂) was visibly molded at 4 weeks and had a higher fat acidity than the other treatments. In the N₂ (99.7% N₂ and 0.3% O₂) and controlled atmosphere (13.5% CO₂, 0.5% O₂, 84.8% N₂) treatments, a fermentation-like odor was detected. When the corn was removed from the modified atmospheres it deteriorated rapidly and was soon contaminated with aflatoxins.     

Indonesian Tapé Ketan Fermentation

Indonesian tapé ketan is a fermentation in which a mold, Amylomyces rouxii Calmette (Chlamydomucor oryzae Went and Prinsen Geerligs), in combination with one or more yeasts such as Endomycopsis burtonii converts steamed rice to a sweet-sour, slightly alcoholic paste. A study was made to determine the biochemical changes that occur in the substrate during fermentation. It was found that the product was ready for consumption after fermentation at 30°C for 36 to 48 h. A. rouxii used about 30% of the total rice solids, resulting in a crude protein of 12% in 96 h, whereas the combination of the mold with E. burtonii reduced total solids by 50% in 192 h, causing crude protein to increase to 16.5%. Soluble solids increased from 5 to about 67% in 36 h and decreased to 12% at 192 h with A. rouxii alone, whereas soluble solids fell to about 8% at 192 h in the fermentation with both the mold and the yeast. The mold, by itself, reduced the starch content of the rice from 78 to 10% in 48 h and to less than 2% in 144 h. The mold plus yeast reduced the starch content to about 18% in 48 h; however the “starch” content did not fall below 6% even at 192 h, presumably because the yeast was producing glycogen, which was determined along with the residual starch. With both the mold and the mold plus yeast fermentations, reducing sugars increased from less than 1% to approximately 5% in 24 h and reached maximum concentration, 16 to 17%, between 36 and 48 h. A. rouxii by itself produced a maximum of about 5.6% (vol/vol) ethanol at 96 h. The highest concentration of ethanol (8%, vol/vol) was produced by the mold plus E. burtonii at 144 h. The mold by itself reduced the starting pH from 6.3 to about 4.0 in 48 h. The combination of the mold and yeast reduced the pH to 4.1 in 144 h. The mold increased total acidity to approximately 6.2 meq of H⁺ per 100 ml, and the combination of the mold and yeast increased the total acidity to 7.8 meq of H⁺ per 100 ml in 192 h. At 48 h there was practically no difference in the volatile acidity (0.20) for the combined fermentation compared with 0.26 meq of H⁺ per 100 ml for the mold fermentation. The mold and at least one species of yeast were required to develop the rich aroma and flavor of typical Indonesian tapé.     

Haliphthoros milfordensis isolated from black tiger prawn larvae (Penaeus monodon) in Vietnam

A marine fungus was isolated from the black tiger prawn Penaeus monodon at Nha Trang, Vietnam, on March 20, 2001 and named isolate NJM 0131. The fungus was identified as Haliphthoros milfordensis from the characteristics of asexual reproduction, and its physiological characteristics were investigated. Although the optimum temperature for growth of the isolate was 25°–30°C, the fungus grew at a wide range of temperatures (15°–40°C). H. milfordensis grew well in 50%–100% seawater, but poorly in PYG agar containing 1.0%–5.0% NaCl and KCl. The fungus grew at a wide range of pH (4.0–11.0) with the optimum pH value of 7.0–9.0. The isolate also showed pathogenicity to swimming crab larvae (Portunus trituberculatus) by artificial infection, but mortality was not high. This is the first report of disease in the black tiger prawn P. monodon in Vietnam caused by H. milfordensis.     

Evaluation of Alternaria crassa for biological control of Jimsonweed: Host range and virulence

An isolate of Alternaria crassa (Saac.) Rands was obtained from a naturally occurring leaf-spotting disease of Jimsonweed (Datura stramonium L.) plants. The fungus was induced to sporulate and used to reproduce the disease on seedlings in greenhouse and field inoculation tests. The fungus grew best at 25–35°C, and germinated best at 25–30°C. Infectivity on Jimsonweed was reduced at temperatures below 20°C and above 30°C. In greenhouse host range studies, conidia of the fungus were highly pathogenic to Jimsonweed, moderately pathogenic to ‘Marion’ and ‘Beefsteak’ tomatoes, and non-pathogenic to several other crop and weed species representing seven botanical families. These findings indicate that A. crassa has potential as a biological herbicide for controlling Jimsonweed.     

Prevalence and development of storage fungi in peanut Arachis hypogaea seed

Summary A batch of peanutArachis hypogaea seed were divided into 4 2-kilogram portions and stored 6 months at 22–28° C. One portion was stored with the moisture content slowly increasing from 4 to 28 %; the other portions were maintained at approximately 4.5, 8.9 and 11.5 %. After 1, 2, 3, 4, and 6 months storage, 100 seed of each treatment were cultured on malt-10 % NaCl agar and the fungi isolated identified. The storage fungi present after intervals of storage were compared with those initially present. In seed stored at 4.4 % moisture,Aspergillus species remained about the same andPenicillium decreased. At 8.9 % moistureA. flavus, A. repens andPenicillium were reduced, andA. amstelodami andA. ruber increased. At 11.5 % moisture, 100% of the seed yieldedA. ruber after 4 months storage and the other storage fungi decreased to 0–2 %. The moisture content of seed stored at 99 % R. H. increased slowly to 28 % and resulted in monthly changes in the dominant fungi. Under such a circumstance with competition between these storage fungi,A. ruber grew best at 12–15 %,A. repens at 18.5 %,A. flavus andPenicillium at 20 %, andA. amstelodami between 20–28 %.Fusarium increased very rapidly as moisture content increased above 18 %.This investigation was supported by Agricultural Research Service, U.S. Department of Agriculture, Contract No. 12-14-100-8179 (34), administered by the Crops Research Division, Beltsville, Maryland.Former Research Associate, North Carolina State University, Raleigh, N. C., currently Research Plant Pathologist, Market Quality Research Division, Agricultural Research Service, United States Department of Agriculture; and Professor, North Carolina State University, Raleigh, N.C.Paper number 2489 of the Journal Series of the North Carolina State University Agricultural Experiment Station, Raleigh, North Carolina.     

Short-term effects of temperature upon the growth of intertidal fucales

The growth rate of five species of intertidal Fucales (Pelvetia canaliculata (L.) Dec. et Thur., Fucus spiralis L., Fucus vesiculosus L., Fucus serratus L., Ascophyllum nodosum (L.) Le Jolis) was measured at temperatures from 2.5 to 35 °C. An increase in temperature immediately causes a high growth rate, and during the first hour it increases linearly with temperature; at 35 °C it is 20 times the control at 7 °C. This acceleration of growth is based mainly on stored photosynthate. After the first few hours the growth rate decreases rapidly, particularly at the highest temperatures. After 2–3 weeks a temperature optimum below 17.5 °C is indicated. High temperatures, 30–35 °C, were lethal to all species, with a survival time corresponding to their vertical zonation in the natural habitat.     

Long-term storage stability of Beauveria bassiana ERL836 granules as fungal biopesticide

Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae) ERL836 has been commercialized under the name ChongchaeSak to control an agricultural insect pest, the western flower thrips Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), in the Republic of Korea. As soon as it was launched in 2017, it became a popular product and has received a positive response. However, study of the storage stability of the fungus ERL836 has yet to be investigated. To determine the optimum conditions for long-term storage, we assessed conidial viability and insecticidal activity of B. bassiana ERL836 according to storage temperature and culture substrate. Viability of B. bassiana ERL836 conidia from mycotized grains (millet and rice) stored at low (4 °C) and moderate (25 and 30 °C) temperatures was maintained at >85% for 24 and 18 months, respectively, along with insecticidal activity. In contrast, the samples stored at 37 °C showed low germination rate (about 80% germination rate for only 5 months). This result suggests that low and moderate temperatures (4 to 30 °C) conserve B. bassiana ERL836 viability and virulence.     

Relationships Between the Population Density of Meloidogyne incognita and Growth of Tobacco

Seedlings of tobacco cultivars resistant (NC95) and susceptible (McNair 30) to Meloidogyne incognita were grown in 15-cm diameter clay pots containing steamed soil infested with 0, l, 2, 4, 8, 16, 32, and 64 eggs of M. incognita per 1.5 cm³ soil. Plants were maintained in the greenhouse for 3 weeks, and then transferred to the field for 12 weeks. Growth of tobacco was expressed separately as dry weight of leaves and as plant height. Least squares regression analysis showed that tobacco growth-nematode density interactions are in agreement with Seinhorst''s exponential model Y = m + (l-m) czp. Tobacco growth was not affected significantly as nematode density was increased from 0 to tolerance levels, which were approximately 2 and 1 eggs per 1.5 cm³ soil for the resistant and susceptible cultivars, respectively. As nematode density was increased beyond tolerance level, tobacco growth decreased sharply until a minimum yield was approached. The minimum leaf weights and plant heights of the resistant cultivar at the highest nematode density were greater than those of the susceptible cultivar.     

Regeneration capacity from buds on roots and rhizomes in five herbaceous perennials as affected by time of fragmentation

Variation in seasonal sprouting pattern from roots and rhizomes of perennial herbaceous plants influence the success of plant proliferation ability, invasiveness and escape from weed control measures. The latter often rely on methods, which repeatedly fragment the underground system, thereby trigger adventitious and axillary buds to sprout, and consequently reduce the amount of stored energy. If carried out at times when no re-growth occurs, treatments will have little effect on weed populations, but cost much in terms of labour and energy. The purpose of this experiment was to determine the seasonal variation in bud sprouting capacity after fragmentation. Five troublesome perennial weed species, collected in northern and southern Sweden, were grown outdoors in Uppsala, Sweden (N 59°49′, E 17°39′), from May 2009 to January 2010. Cut root and rhizome fragments, taken at two weeks intervals from July to January, were used to evaluate bud sprouting capacity, which was statistically analyzed using generalized additive models. In Elytrigia repens from southern Sweden and Sonchus arvensis sprouting capacity was significantly impaired during a period from September to November. In Equisetum arvense and Tussilago farfara sprouting was low between July and November where after it increased. In contrast, Cirsium arvense and E. repens from northern Sweden sprouted readily throughout the period. Except for E. repens, a model by populations was significantly better than one based on latitudinal origin. The result suggests a species-specific timing of treatments in weed management, avoiding the non-effective autumn period for E. arvense, S. arvensis and T. farfara, and in some cases in E. repens.