scholarly journals Relationship between Sitona lepidus larval numbers and white clover seed production

2001 ◽  
Vol 54 ◽  
pp. 141-146
Author(s):  
P.J. Gerard

Plots of two cultivars of white clover (Trifolium repens) Grasslands Prestige (smallleaved early flowering) and Grasslands Kopu (largeleaved later flowering) were established in coldframe beds Clover root weevil (Sitona lepidus) larval numbers were manipulated to obtain winter larval densities ranging from 0 to over 1000/m2 Increasing winter larval densities increased Prestige seed production (g/m2) when harvested on 28 December and 10 January and the trend was still evident on 24 January No such relationships were found in Kopu for the early and middle harvests but at the late harvest increasing winter larval densities had a negative impact on seed production The results indicate that the effect of clover root weevil larvae on second year clover seed crops may vary substantially between cultivars and may even be positive rather than negative

Author(s):  
P.J. Gerard ◽  
T. Eden ◽  
W. Tozer

A small plot trial was undertaken in the Waikato to determine the potential impact of Sitona lepidus adults on white clover seed production. Five densities of adult weevil were caged on 1 m2 plots from the time of peak adult emergence in November 1998 until harvest in late January 1999. In the laboratory, weevil adults were found to severely damage clover inflorescences when no leaves were present. Although feeding damage on leaves was highly visible in the field plots, with over 80% of the leaflets damaged at the highest density of 600 adults/m2, weevil adults were found to have no effect on flowering or seed production.


1996 ◽  
Vol 6 ◽  
pp. 40-40
Author(s):  
B.L. Mccloy ◽  
S.R. White

In recent years there has been an increase in the number of white clover seed crops taken for a second harvest. Traditionally yields from second year crops are substantially lower than first year crops. A trial was established investigating techniques to increase yields in second year crops. The trial was located in a dryland crop of white clover (cv. Grasslands Demand) 4 km east of Methven, mid Canterbury. It involved 10 herbicide treatments and 8 'inter-row' treatments arranged in a split block design. Number of mature flower heads were recorded on all treatments at harvest as an indirect estimate of yield. Additionally, selected treatments were cut and collected using a rotary type mower, threshed, and machine dressed for direct estimates of seed yield. Flower number and machine dressed seed yield were significantly (P


Author(s):  
В. Золотарев ◽  
Н. Переправо

Среди многолетних трав клевер ползучий (Trifolium repens L.) является одним из лучших бобовых компонентов для создания культурных луговых и пастбищных агрофитоценозов в районах с умеренным климатом. На основе биологических особенностей клевера ползучего показана эффективность использования этой культуры для лугопастбищного кормопроизводства страны. Дан краткий анализ опыта возделывания клевера ползучего за рубежом. Показано значение хозяйственно полезных признаков сортов на эффективность их использования в травосмесях. Приведён материал по ботанической классификации разновидностей клевера ползучего и особенностям хозяйственного использования сортов разных морфотипов. Показана различная эффективность импортных и отечественных сортов клевера при их возделывании в почвенно-климатических условиях России. В настоящее время в Государственном реестре селекционных достижений, допущенных к использованию на территории РФ, зарегистрировано 27 сортов клевера ползучего, из них девять (33) отечественной селекции. Актуализирована необходимость усиления селекционной работы по выведению новых сортов, адаптированных к разнообразным почвенно-климатическим условиям и определённым режимам пастьбы. На основании этого обозначены направления селекции. Высокий рыночный спрос вызывает необходимость организации товарного семеноводства клевера ползучего сортов отечественной селекции. Установлено, что основной объём семян завозится из-за рубежа. Однако сорта зарубежной селекции мало приспособлены для произрастания в континентальном климате России. В статье в ретроспективе показано состояние и перспективы семеноводства клевера ползучего в России, включая систему воспроизводства его семян. Представлена научно обоснованная потребность в необходимых объёмах производства посевного материала на разных этапах репродуцирования для обеспечения лугопастбищного кормопроизводства. Для существенного увеличения сборов семян клевера ползучего предложено широко внедрять в производство сортовые посевы при оптимальных технологиях их выращивания, что позволит раскрыть потенциальные возможности каждого сорта в конкретных почвенно-климатических условиях и повысить урожайность семян в 23 раза. White clover (Trifolium repens L.) is one of the best perennial legume components for grassland and pasture ecosystems in regions with temperate climate. This report describes the effectiveness of this crop in forage production basing on its biological traits. It presents the experiment on clover cultivation abroad. The influence of economically important traits is shown on clover performance in grass mixtures. The article includes white clover botanical classification and cultivation methods of different morphotypes. Performances of foreign and domestic varieties were tested under Russian environment. Currently State Register for varieties accepted for cultivation in Russia lists 27 white clover varieties, and nine of them (33) are domestic. It is important to work further on breeding of new clover varieties adapted to various conditions. There is a high demand for white clover seeds of domestic origin. The main part of white clover comes from abroad. However, such varieties poorly grow under Russian climate. This paper shows the state and perspectives of white clover seed production in Russia. When producing grassland forage efficient seed production of this crop is of great importance. Introduction of white clover varieties to particular regions is a way to stimulate its seed production using optimal cultivation techniques.


Weed Science ◽  
1975 ◽  
Vol 23 (6) ◽  
pp. 441-444 ◽  
Author(s):  
W. O. Lee

Winter applications of paraquat (1,1′-dimethyl-4,4′-bipyridinium ion) or combinations of paraquat with diquat [6,7-dihydrodipydrido (1,2-α: 2′,1′-c) pyrazinediium ion], propham (isopropyl carbanilate), or pronamide [3,5-dichloro-N-(1,1-dimethyl-2-propynyl)benzamide], usually controlled both winter annual grass and broadleaf weeds in established white clover (Trifolium repensL. ‘New Zealand,’ ‘Louisiana S-1,’ and ‘Tillman’). Diquat controlled broadleaf weeds, but was less effective than paraquat or combinations of paraquat with diquat, propham, or pronamide for grass control. Dichlobenil (2,6-dichlorobenzonitrile) controlled weeds in some experiments. Pronamide and propham usually controlled grass weeds but not broadleaf weeds. In experiments in which clover seed production differed significantly, paraquat or combinations of paraquat with propham or pronamide usually resulted in higher yields than the check. Yields increased more often where treatments included paraquat.


Weed Science ◽  
1972 ◽  
Vol 20 (4) ◽  
pp. 330-331 ◽  
Author(s):  
William O. Lee

Seed fields of white clover (Trifolium repens L. ‘New Zealand’ and ‘Louisiana S-1′) were treated with the dimethylamine salt and the isooctyl ester of 4-(2,4-dichlorophenoxy)-butyric acid (2,4-DB). Rates of application were 0.56, 1.12, and 1.68 kg/ha. Applications were made at the vegetative, bud, and flowering stages of growth. All treatments applied at the vegetative and bud stages of growth significantly reduced white clover seed production. Reductions in clover seed production usually became more severe as the rate of 2,4-DB increased.


2014 ◽  
Vol 67 ◽  
pp. 250-255
Author(s):  
P.J. Gerard ◽  
K.M. O'Donnell

Western clover (Trifolium occidentale) is a diploid perennial clover that is reported to be one of the progenitors of white clover (Trifolium repens) The ability to produce hybrids between T repens and T occidentale provides an opportunity to introduce factors to improve white clover tolerance to common stress factors A series of assays was undertaken to compare the feeding and performance of two contrasting pests on two T occidentale lines and two T repens cultivars Clover root weevil (Sitona lepidus) adults showed a preference for T repens but this diminished if weevils had been previously exposed to T occidentale Weevil longevity feeding levels and oviposition were comparable over 32 days indicating T occidentale is a host plant for adult S lepidus Clover flea (Sminthurus viridis) showed a strong preference for T repens over T occidentale in a choice test and higher feeding levels on T repens in the nochoice test


Author(s):  
B.M. Cooper ◽  
J.R. Crush ◽  
D.R. Woodfield ◽  
B.E. Willoughby ◽  
K.A. Panckhurst

Clover root weevil (CRW) has now spread through the northern North Island, and south into Taranaki and Hawke's Bay r egions. Sever e infestations can decimate white clover in pasture. In 1998, 2000 and 2002, trials were estab lished on a Warkworth Northland dairy farm to test a range of legume species for resistance or tolerance to CRW damage. Trial lines were regularly assessed for relative vigour and levels of CRW damage. No plant resistance w as identified among white clover, red clover, lucerne, Lotus corniculatus, Lotus pedunculatus or Caucasian clover seed lines. A few lines were adapted to the site and showed tolerance to CRW. Red clover suf fered the least damage and tolerant selections were made from a creeping red clover and nine white clover lines. Two further trials confirmed that red clover showed the least damage. Further cycles of selection are required to develop the potential tolerance shown in field tests. Red clover or a well-adapted white clover offers potential to cope with the CRW stress. Keywords: clover root weevil, clover selections, legume tolerance, Sitona lepidus


1985 ◽  
Vol 2 ◽  
pp. 67-73
Author(s):  
P.T.P. Clifford ◽  
M.P. Rolston ◽  
W.M. Williams

Buried hard seed from seed returned to the soil during harvesting and incorporated by cultivation, poses the greatest threat of contamination. When a different white clover (Trifolium repens L.) is sown, contamination will occur when hard seeds within the germinating zone soften and emerge. Harvest losses can return 40 to 210 kg/ha of hard seeds to the soil. Flowering management and efficient harvesting are necessary to minimise quantities of hard seed returned to the soil. For a buried seed load of 845/m* in the germinating zone of a cultivated seed bed at sowing in March, 8% of that seed load gave rise to establishing plants of which one-third (19/m') were surviving in mid-October. At closing the percentage crop contamination within the sown row was directly proportional to the within-row seeding rate of the sown cultivar. At wider-than-normal row spaces, (45 cm compared with 15 cm) either inter-row cultivation or spraying for removal of contaminants was necessary at closing to reduce contaminants to a density similar to that in 15 cm spacing treatments. Physical contamination of the harvested seedline, compared with levels present at closing, had doubled for normal, but trebled for wider-than-normal spacings. Lowest percentage physical contamination of a seedline gained was 13% for a 6 kg/ha seeding at 15 cm spacings. The results indicate that successful cultivar change on many areas will be difficult. A buried seed count is considered an essential guideline to aid choice of paddock. Future management systems now being developed, include the use of herbicides and direct drilling, and should help to minimise this problem. Keywords: White clover, Trifolium repens, seed production, contamination, cultivar change, harvest losses, hard seed, cultural practices.


1980 ◽  
Vol 1 ◽  
pp. 70-73
Author(s):  
J.K. Lay

Irrigation has removed much of the risk associated with white clover seed production in an area of poorly distributed annual rainfall of 530 mm. Machine-dressed seed yields range between 540 and 900 kg/ha. The importance of minimizing harvesting losses is emphasized. Key words: Trifolium repens, seed production, irrigation.


1985 ◽  
Vol 2 ◽  
pp. 33-35
Author(s):  
John Mccartin

Autumn sown white clover after wheat results in good white clover establishment and large areas can be sown. Direct drilling white clover into barley stubble in the autumn also gives very good white clover establishment. Other methods which include ryegrass and white clover sown together in autumn, sowing with autumn wheat, undersowing barley and processed peas in the spring and oversowing autumn wheat in the spring are less successful. Keywords: White clover, Trifolium repens,


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