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1.
Abstract

Brassicaceae plants have the potential as part of an integrated approach to replace fumigant nematicides, providing the biofumigation response following their incorporation is not offset by reproduction of plant-parasitic nematodes on their roots. Forty-three Brassicaceae cultivars were screened in a pot trial for their ability to reduce reproduction of three root-knot nematode isolates from north Queensland, Australia: M. arenaria (NQ1), M. javanica (NQ2) and M. arenaria race 2 (NQ5/7). No cultivar was found to consistently reduce nematode reproduction relative to forage sorghum, the current industry standard, although a commercial fodder radish (Raphanus sativus) and a white mustard (Sinapis alba) line were consistently as resistant to the formation of galls as forage sorghum. A second pot trial screened five commercially available Brassicaceae cultivars, selected for their biofumigation potential, for resistance to two nematode species, M. javanica (NQ2) and M. arenaria (NQ5/7). The fodder radish cv. Weedcheck, was found to be as resistant as forage sorghum to nematode reproduction. A multivariate cluster analysis using the resistance measurements, gall index, nematode number per g of root and multiplication for two nematode species (NQ2 and NQ5/7) confirmed the similarity in resistance between the radish cultivar and forage sorghum. A field trial confirmed the resistance of the fodder radish cv. Weedcheck, with a similar reduction in the number of Meloidogyne spp. juveniles recovered from the roots 8 weeks after planting. The use of fodder radish cultivars as biofumigation crops to manage root-knot nematodes in tropical vegetable production systems deserves further investigation.  相似文献   

2.
The antifeedants triphenyltin acetate and hydroxide and neem seed kernel extracts in two concentrations each, were evaluated as control measures against the sorghum shoot fly,Atherigonu varia soccata Rond. in comparison with the insecticides presently used for this purpose. The antifeedants appeared to be partially effective and were less active than the insecticides.  相似文献   

3.
Abstract

In the present study the incidence of Chilo partellus and its mortality due to natural enemies on sorghum intercropped with cowpea and maize were investigated in the 1984–6 cropping seasons. The lowest larval density was recorded in sorghum/ cowpea intercrop (mean 0. 18 larvae/plant); and the highest density in sorghum/maize (mean 1. 8 larvae/plant), although significant differences in larval density were observed only in three out of five seasons. Life table analysis showed first‐generation mortality of C. partellus to be highest in the age interval from egg to early‐instar larva (95–98% real mortality) and attributable mainly to predation; first‐generation mortality due to parasitoids and pathogens was negligible. Significantly higher (P < 0. 05) apparent pupal mortality due to Dentichasmias busseolae (Heinrich) (Ichneumonidae), in the second generation occurred in sorghum/cowpea (42.8%) than in sorghum/maize (12.5%). It was concluded that predators play a significant role and that intercropping sorghum with cowpea or maize does not interfere with their activity. Intercropping sorghum with cowpea gave nearly 40% higher yield index than sorghum monocrop. The implications of these findings on management  相似文献   

4.

A survey was conducted to gain insight into the perceptions of Lesotho's farmers with regard to insect pests of maize and sorghum, to identify management practices that could impact on stalk-borer numbers and to shed light on other farming practices such as variety selection and crop residue management. Field studies were conducted to determine the incidence and distribution of Busseola fusca (Lepidoptera: Noctuidae) and Chilo partellus (Lepidoptera: Pyralidae) larvae in sorghum and maize residues and to determine the effect of certain crop residue management practices on stalk-borer survival. Results indicated that farmers regard stalk-borers as important pests that sometimes need to be controlled. However, most farmers never apply control measures, mainly due to lack of resources. Residues of maize and sorghum plants are largely used as animal fodder with maize being cut and fed to animals after harvest. Sorghum crop residues are largely left on fields after harvest to be used by free-grazing animals. While stacks of maize stalks were not important in the winter survival of B. fusca larvae, stacking of sorghum ensures winter survival of C. partellus larvae. Detasselling of maize plants is commonly done at plant senescence and the upper halves of plants are fed to animals. Detasselling of maize plants had no effect on the number of borer larvae in plants at harvest.  相似文献   

5.
Plants of soybean (Glycine max) and sorghum (Sorghum bicolor) were grown either alone or in combination with 1, 2, 4, 8 and 16 Amaranthus dubius plants per pot in controlled environment chambers at 31/24 and 25/18°C day/night temperatures. Above-ground dry weights, leaf areas and heights were measured at 17 and 35 days after planting. Growth of both species increased with temperature. At the second harvest, at both temperatures, even one A. dubius plant per pot had a significant effect on growth of the crop species, and the effects of the two highest densities were equivalent. Shoot dry weights of A. dubius plants were significantly lower when grown with soybean than with sorghum at the same conditions. Linear regressions showed that the dry weights of the crop species were more highly correlated with biomass than with numbers of the interfering weeds, and suggest that soybean may be more affected by an increase in abundance of A. dubius than is sorghum.  相似文献   

6.
Abstract

Grain sorghum (Sorghum bicolor (L.) Moench) is the dominant crop in North Yemen agriculture, covering about 70–80% of the arable land. Weed control is still carried out mainly by hand. Many of the weeds are used as fodder for animals. A total of 137 weeds was collected in sorghum. Most frequent were Cynodon dactylon (L.) Pers. and Cyperus mtundus (L): their importance decreased, however, under a well‐established sorghum crop providing good shade cover and under conditions of increased crop fertilization with mineral nitrogen. Under these conditions, for example, Commelina spp. and Flaveria trinerva (Spreng.) Mohr became commoner. Thus increased use of nitrogen altered the nature and hierarchy of the weed flora. Relationships between the indicator figures of the weeds and the habitat, as defined by Ellenberg, were confirmed. Traditional methods of weed control have so far worked well, as witness an average cover of 60% sorghum and 20% weeds. In future, however, rising costs and labour shortages will increase the demand for less time‐consuming weed control strategies.  相似文献   

7.
Historical records report Fusarium moniliforme sensu lato as the pathogen responsible for Fusarium diseases of sorghum; however, recent phylogenetic analysis has separated this complex into more than 25 species. During this study, surveys were undertaken in three major sorghum‐producing regions in eastern Australia to assess the diversity and frequency of Fusarium species associated with stalk rot‐ and head blight‐infected plants. A total of 523 isolates were collected from northern New South Wales, southern Queensland and central Queensland. Nine Fusarium species were isolated from diseased plants. Pathogenicity tests confirmed F. andiyazi and F. thapsinum were the dominant stalk rot pathogens, whilst F. thapsinum and species within the F. incarnatum–F. equiseti species complex were most frequently associated with head blight.  相似文献   

8.
Abstract

Seasonal incidence of shootfly, Atherigona naqvii Steyskal was studied in wheat sown on nine dates at approximately fortnightly intervals from 1 October to end of January during the 1973–74 to 1976–77 seasons at Jaipur, India. During the season the pest remained more active from the second fortnight of October to mid-December and again during February and March. These fluctuations appear to have a positive correlation with maximum and minimum temperatures while relative humidity and rainfall did not have any influence. The winter low temperatures during mid-December to mid-February arrested the flies' activity. The crop sown between mid-November and mid-December was found to be almost free from shootfly and no control measures are needed. However, early and late sown crops remained prone to attack.  相似文献   

9.
Nematodes     
Abstract

Studies were carried out on farms to evaluate potential control practices which could be constituted into a package of recommendations for the control of Striga hermonthica in the Gambia. ICSV 1002, a variety of sorghum, was identified as being relatively more tolerant to Striga and to the common insect pests of sorghum. Spot treatment of emerged Striga shoots with 2% solution of product paraquat using a pistol‐grip hand sprayer was found to control Striga without stimulating regrowth, improved yields and was more acceptable and cost‐effective than handpulling of the shoots in early millet and sorghum. Where there might be objections to the use of paraquat because of its toxicity hazards, a mixture of 2,4‐D (1 % soln.) plus glyphosate (1 % soln.) or 2,4‐D (2% soln.) was a useful substitute. A tentative control package consisting of ICSV 1002, spot spraying of Striga shoots with paraquat, and side dressing of urea fertilizer at 30 kg N/ha at 4 w.a.p. was tested at two sites against farmers’ practice on pilot scale. Infestation of Striga was reduced and yields were increased by 119% and 37% by the package at the two sites.  相似文献   

10.
The study deals with the tachinid parasitoids ofAncyrosoma leucogrammes (Gmelin) (Heteroptera: Pentatomidae):Clytiomya dupuisi Kugler,Clytiomya sola (Rondani) andGymnosoma clavatum (Rohdendorf) (Diptera: Tachinidae). All species are recorded for the first time as parasitoids ofA. leucogrammes, andC. dupuisi was reared for the first time from a host. The parasitization rates ofC. dupuisi on adults ofA. leucogrammes varied from 7% to 9% between 1994 and 1999.C. sola andG. clavatum were reared in only small numbers. http://www.phytoparasitica.org posting July 10, 2003.  相似文献   

11.
Abstract

Metsulfuron methyl (Ally‐Dupont), a sulphonylurea herbicide, was tested at rates of 0.5–2.0 g a.i./ha for the control of Striga hermonthica (Del.) Benth. in two cultivars of sorghum in pot experiments. There was good to excellent Striga control at 1.0–2.0 g a.i./ha applied either pre‐emergence or post‐emergence to CSH‐1 or N‐13 sorghum. The herbicide was unacceptably toxic to the Striga‐susceptible CSH‐1 cultivar when applied pre‐emergence, thus eroding any benefits of Striga control. In the Striga‐tolerant N‐13 cultivar there were considerable increases in the growth of infected plants. The herbicide was better tolerated from post‐emergence applications by both cultivars, and CSH‐1 plants recovered enough growth from Striga infection to produce grain yields at 1–5 and 2.0 g a.i./ha. Herbicide application at 4 weeks after planting sorghum was less damaging than at 2 weeks. Herbicide safening with 1,8‐naphthalic anhydride did not provide any additional benefits with post‐emergence application. The efficacy of the pre‐emergence herbicide was similar with surface or incorporated application.  相似文献   

12.
Sanitation from harvest to storage is a key factor in eliminating sources of infection and reducing levels of mycotoxigenic fungal invasion, and thereby mycotoxin contamination. This study was conducted at Haramaya University, Eastern Ethiopia to investigate the effects of threshing methods on fungal invasion and mycotoxin contamination of sorghum grain. The methods included threshing on bare ground, cow-dung-painted ground, concrete asphalt and canvas. The threshed grain was kept separately in bags in three replications in a completely randomized design and stored for five months. The results revealed that all the sorghum grain samples taken from different threshing methods were contaminated with both Aspergillus and Fusarium species. There were variations in fungal invasion between samples taken immediately after threshing and stored samples. The level of Aspergillus spp. invasion was much higher in the latter in sorghum grain threshed on bare ground. The concentration of aflatoxin B1 was gradually increased, whereas the total fumonisin concentration was decreased with the storage duration both in 2013 and 2014. On stored sorghum grain, the highest (1.97 µg kg?1) and the lowest (0.70 µg kg?1) mean aflatoxin B1 concentrations were recorded from sorghum grains threshed on bare ground and on canvas, respectively. Sorghum grain obtained from canvas threshing method had significantly lower mean total fumonisin content (142.5, 54.9 µg kg?1) than grain from the other methods at threshing. The current work clearly demonstrated the effect that threshing might have on fungal invasion and mycotoxin contamination of sorghum grains. .  相似文献   

13.
The ability of the herbicide safeners, BAS-145138 (1-dichloroacetyl-hexahydro-3,3,8a-trimethyl-pyrrolo(1,2a)pyrimidin-6(2H)-one), dichlormid (N,N-diallyl-2,2-dichloroacetamide), flurazole (phenylmethyl ester), and MG-191 (2-dichloromelhyl-2-methyl-1,3-dioxolane) for preventing metazachlor injury to maize (Zea mays L.) and sorghum (Sorghum bicolor L.) seedlings were compared with their effects on 14C-metazachlor metabolism to a glutathione (GSH) conjugate, effects on non-protein thiol contents (mainly GSH) and effects on Glutathione S-transferase (GST) activity in these two species. Sorghum shoot growth was reduced by 41% and maize shoot growth was reduced by 54%, by metazachlor concentrations in vermiculite nutrient culture of 0·6 μM and 7·5μM, respectively. In this system, all four compounds had significant activity as safeners for metazachlor in both sorghum and maize seedlings. BAS-145138 and flurazole were the most effective safeners in maize and sorghum, respectively. In the absence of safeners, the rate of non-enzymatic conjugation of metazachlor and GSH was much greater than the enzymatic rate. However, the rate of enzymatic conjugation of metazachlor with GSH was increased by safener treatment in both maize and sorghum. Safener effectiveness was highly correlated with increases in 14C-metazachlor uptake and metabolism in both species. Safener effectiveness was more highly correlated with safener effects on GST activity in maize or sorghum when 14C-metazachlor was used as the substrate than when the non-specific CDNB (1-chloro-2,4-dinitrobenzene) was used as the substrate. Safener effectiveness was also strongly correlated with safener effects on GSH levels in sorghum, but not in maize, possibly because of the greater importance of non-enzymatic conjugation of metazachlor with GSH in sorghum as compared to maize.  相似文献   

14.
Abstract

Agroecosystems in the tropics include growing two or more crops in diverse polycultural patterns. In Kenya, cowpea Vigna unguiculata (Walp.) is grown in combination with cereals such as maize and sorghum, perennial legumes such as pigeon peas and root crops such as cassava and sweet potatoes. In the present investigations, field experiments were conducted to study the incidence and damage caused by Clavigralla tomentoscollis Germ, and C. shadabi after flowering, on cowpea intercropped with maize. It was evident from the present studies that C. tomentoscollis and C. shadabi were more prevalent on cowpea during the first season rather than during the second season. Both species had a preference for feeding on cowpea intercropped with maize than when it was grown in pure stands. Consequently more pod damage was recorded on cowpea planted with maize. It was therefore concluded that this agricultural system, which is commonly practised by small‐scale farmers in Kenya, is undesirable from the point of view of bug damage.  相似文献   

15.
The effect of food plants [Acacia elatior Brenan, A. tortilis (Forssk.) and A. nilotica (L.) Del.] on the development time of Gonometa postica Walker (Lepidoptera: Lasiocampidae) larvae and the quality of their cocoons was studied in the Imba and Mumoni forests of Mwingi, Eastern Kenya, during the long (March-May) and short (October-December) rainy seasons of 2006 and 2007. Larvae were reared in semi-captivity in net sleeves attached to branches of the plants. The period between hatching of eggs and spinning of cocoons, as well as their weight, as determinants of cocoon quality were recorded. In addition, collections of cocoons from the wild were done in the two forests from the same host plants for assessment of their quality. In the cage experiment, larval development period and quality of cocoons differed according to food plants, seasons and sites, whereas quality of cocoons sampled from the wild habitat was similar for all food plants and seasons but varied according to site. Generally, there was a positive correlation between weight of cocoon, its length and width for the two seasons for both the semi-captive population and those from the wild. Larvae reared on A. elatior had a shorter development period and higher cocoon quality than those raised on A. tortilis and A. nilotica. Generally, temperature and relative humidity significantly influenced larval development time and the effect was both positive and negative. Rainfall was generally higher in Mumoni than in Imba. The implications of the above findings for the semi-captive rearing of G. postica to increase the quality of cocoons are discussed.  相似文献   

16.
Tephritid parasitoids reared from 26 different host fruit species showed remarkably little diversity across 21 Brazilian counties. The majority of the parasitoids (81.4%) belonged to the braconid subfamily Opiinae, with Doryctobracon areolatus (Szépligeti) the most commonly encountered species. Four other opiines, namely D. brasiliensis (Szépligeti), Opius bellus Gahan, Optus sp. and Utetes (Bracanastrepha) anastrephae (Viereck) were also reared, but in much smaller numbers. Asobara anastrephae (Muesebeck), an alysiine braconid parasitoid of tephritids, accounted for an additional 18–6% of the individuals reared from tephritids. The hosts and distribution patterns of the braconid parasitoids of Brazilian fruit‐infesting Tephritidae are summarized.  相似文献   

17.
Over the last two decades, the demand for organic products has grown rapidly in the world due to increased concern about side effects of pesticides on the environment and human health. Studies were conducted in organic lettuce (Lactuca sativa L.) from 2004 to 2005 at the Black Sea Agricultural Research Institute in Samsun, Turkey, to determine the suppressive effects of summer cover crops on weeds. The experiment was arranged in a randomized complete block design with four replications. Treatments consisted of grain sorghum [Sorghum bicolor (L.) Moench.], sudangrass [Sorghum vulgare Pers. var. sudanense (Piper) Hitchc.], hairy vetch (Vicia villosa Roth.), grain amaranth (Amaranthus cruentus L.), pea (Pisum sativum L.) and bare ground with no cover crop. Weed density and total weed dry biomass were assessed before and at 14, 28, and 56 days after incorporation (DAI) of the cover crops. The cover crops produced between 1.2 and 3 t ha−1 biomass and grain sorghum produced more dry matter than any other species in both years. After incorporation of the cover crops, hairy vetch and sorghum treatments showed fewer weed species, and lower weed density than the other cover crops in both years. Hairy vetch, grain sorghum, and sudangrass were the most effective cover crops and reduced total weed dry biomass by 90.3%, 87.4%, and 86.9% in 2004, and by 88%, 86.3%, and 85.2% in 2005, respectively. Cover crop residue suppressed many broadleaved weed species but failed to control grass weeds. Hairy vetch treatments produced the highest yield, followed by sudangrass and grain sorghum. Yields with grain amaranth and pea were similar to that of the control. These results indicate that hairy vetch, grain sorghum, and sudangrass can be used to suppress weeds in early season of organic lettuce production.  相似文献   

18.
Abstract

Sorghum halepense (L.) Pers. (Johnson grass) is an important weed in many countries. In Australia it invades crop lands, provides a harbour for diseases and insect pests of sorghum and maize, contaminates sorghum grown for seed and constitutes a safety hazard along roadsides.  相似文献   

19.
Abstract

Field research was conducted near Hyderabad, India, during 1981 and 1982 to investigate zero‐tillage and reduced‐tillage systems for production of sorghum (Sorghum bicolor (L.) Moench.) under semi‐arid tropical conditions. Part of the investigation compared post‐seeding hand weeding and herbicide treatments for weed control efficacy. The results showed that shallow pre‐seeding tillage was just as effective as deep cultivations in producing high sorghum fodder and grain yields provided weeds were controlled after crop emergence. Both tillage regimes were more effective than a no tillage regime which received only a mixture of glyphosate and 2,4‐D prior to seeding. Post‐seeding weed control practices were essential to maintain high fodder and grain yields of sorghum. Hand weeding and inter‐row blade harrowing were more effective than atrazine applied pre‐emergence or 2,4‐D applied post‐emergence.  相似文献   

20.
Monochamus galloprovincialis Olivier (Coleoptera: Cerambycidae) is one of the vectors of the pinewood nematode Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle (Nematoda: Parasitaphelenchidae), the causal agent of pine wilt in susceptible pine trees. It is therefore important to study both the biological and ecological characteristics of the beetle. In this study reproductive potentials of female beetles reared on two pine species were investigated under laboratory conditions and compared using fertility tables constructed for beetles reared on each tree species. Beetle population parameters were compared between tree species. The intrinsic rate of increase and associated population parameters of beetles reared on Pinus sylvestris L. were consistently higher than those reared on P. nigra Arnold. This result suggests that P. sylvestris has a significantly greater positive effect on the reproductive potential of M. galloprovincialis populations than does P. nigra.  相似文献   

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