Summer Cabbage Research Articles

Diversity of Bacterial Soft Rot-Causing Pectobacterium Species Affecting Cabbage in Serbia

The aim of this work was to identify and characterize the pectolytic bacteria responsible for the emergence of bacterial soft rot on two summer cabbage hybrids (Cheers F1 and Hippo F1) grown in the Futog locality (Bačka, Vojvodina), known for the five-century-long tradition of cabbage cultivation in Serbia. Symptoms manifesting as soft lesions on outer head leaves were observed during August 2021, while the inner tissues were macerated, featuring cream to black discoloration. As the affected tissue decomposed, it exuded a specific odor. Disease incidence ranged from 15% to 25%. A total of 67 isolates producing pits on crystal violet pectate (CVP) medium were characterized for their phenotypic and genotypic features. The pathogenicity was confirmed on cabbage heads. Findings yielded by the repetitive element palindromic-polymerase chain reaction (rep-PCR) technique confirmed interspecies diversity between cabbage isolates, as well as intraspecies genetic diversity within the P. carotovorum group of isolates. Based on multilocus sequence typing (MLST) using genes dnaX, mdh, icdA, and proA, five representative isolates were identified as Pectobacterium carotovorum (Cheers F1 and Hippo F1), while two were identified as Pectobacterium versatile (Hippo F1) and Pectobacterium odoriferum (Hippo F1), respectively, indicating the presence of diverse Pectobacterium species even in combined infection in the same field. Among the obtained isolates, P. carotovorum was the most prevalent species (62.69%), while P. versatile and P. odoriferum were less represented (contributing by 19.40% and 17.91%, respectively). Multilocus sequence analysis (MLSA) performed with concatenated sequences of four housekeeping genes (proA, dnaX, icdA, and mdh) and constructed a neighbor-joining phylogenetic tree enabled insight into the phylogenetic position of the Serbian cabbage Pectobacterium isolates. Bacterium P. odoriferum was found to be the most virulent species for cabbage, followed by P. versatile, while all three species had comparable virulence with respect to potato. The results obtained in this work provide a better understanding of the spreading routes and abundance of different Pectobacterium spp. in Serbia.

Weed Suppression, Nitrogen Availability, and Cabbage Production Following Sunn Hemp or Sorghum-sudangrass

Cover crops included in a crop rotation can help increase nitrogen (N) availability to subsequent crops, raise soil organic matter, and suppress emergence and growth of various weed species. However, weed suppression by cover crops has mostly been investigated shortly after cover crop termination and not over a longer period spanning into the next cropping season. The effects of sunn hemp (Crotalaria juncea) and sorghum-sudangrass (Sorghum ×drummondi) planted the previous year on N availability before transplanting of late summer cabbage (Brassica oleracea), weed germination and growth, and cabbage yield was examined in field studies conducted in 2018 and 2019 at Pittstown, NJ. Results established that there was little evidence for a functional difference in soil N availability for fall cabbage production because of previous cover crop type. Heavy rainfall events both years may have caused major losses of available N that might otherwise be expected to come from N mineralization of residues of legume cover crop like sunn hemp. During the cover crop season, smooth pigweed (Amaranthus hybridus) and common lambsquarters (Chenopodium album) dry biomass was 77% and 82% lower, respectively, in sorghum-sudangrass compared with sunn hemp plots. The subsequent season following sorghum-sudangrass cover crop, dry biomass of broadleaf weeds was lower by 74% and 56% in June and July, respectively, compared with preceding sunn hemp. Smooth pigweed, common lambsquarters, and hairy galinsoga (Galinsoga quadriradiata) were the weed species most consistently affected by preceding sorghum-sudangrass cover crop with biomass decreased by up to 80%, 78%, and 64%, respectively. Thus, it appears that sorghum-sudangrass can provide suppression of some broadleaf species over a relatively long period and is indicative of sorghum-sudangrass allelopathic activity. On the contrary, density and biomass of grassy weeds as well as commercial yield of transplanted cabbage were unaffected by the preceding cover crop. These results suggest that sorghum-sudangrass cover crop could be integrated to transplanted cole crop rotation for providing weed suppression benefits without altering crop yield in New Jersey organic vegetable cropping systems.

Impact of Irrigation Water Source on Microirrigation Systems Performance and Productivity of Leaf Vegetable Crops تأثیر مصدر ماء الری على آداء نظم الری الدقیق وانتاجیة محاصیل الخضر الورقیة

Two field experiments were carried out during summer seasons of 2019 and 2020 in Horticulture farm, Faculty of Agricultural, Kafr El-Sheikh University, North of the Nile Delta, Egypt, having a clay textured soil to evaluate the effect of drainage of fish ponds on microirrigation systems performance and summer cabbage production. Study variables were; two microirrigation systems (drip system D and microsprinkler system MS), two sources for irrigation (traditional water “TW” and drainage of fish ponds “DF”) and three nitrogen doses (100% N, 70% N and 40% N). For traditional water “TW” (100% N) only was applied. The results referred to that, “DF” increased the reduction in emitter flow rate at end of growing season comparing with “TW”. The lowest reduction was achieved by (TW+ 100% N) as 6.1 and 3.0 % for “D” and “MS” systems respectively. The highest uniformity coefficient (CU) at end of growing season achieved by (TW+ 100% N) as 87 and 84 % for “D” and “MS” systems respectively. “D” system achieved the highest head yield while “MS” system achieved the highest head diameter. The highest head yield was achieved by (DF + 100% N) as 110 and 87.4 ton/fed. for “D” and “MS” respectively. The highest values of water productivity were obtained by (DF + 100% N) as 49.7 and 44.7 kg/m3 for “D” and “MS” respectively. The highest values of nitrogen productivity were obtained by (DF + 40% N) as 1170.8 and 1045.8 kgyeild/kgN for “D” and “MS” respectively.

Eco friendly management of major Lepidopteran insect pests of summer cabbage by six commonly used botanicals

Eco friendly management of major Lepidopteran insect pests of summer cabbage by six commonly used botanicals

정식일 이동에 따른 배추 잠재수량성의 시공간적 변화 전망

주산지 배추재배농가에서 기후변화 적응수단의 하나로 사용할 수 있는 것이 정식기 이동이다. 본 연구에서는 여름배추 품종을 대상으로 주어진 정식일부터 매일 기온의 경과에 의해 최적수확기를 예측하고, 결정된 생육 기간 중 기온자료에 의해 배추의 잠재수량(생체중)을 추정할 수 있는 방법을 고안하였다. 이를 위해 정식기 이동에 따른 생육기간 중 기후조건 변화를 온도 기반 열단위로 표현하고, 이를 생육기와 결구기에 맞게 조절한 발육 속도함수에 적용하여 생리적 성숙기를 추정하는 생물계절모형을 개발하였다. 다음에는 생물계절모형에 의해 결정된 재배가능기간에 대하여 매일 열단위 누적에 의해 여름배추의 잠재수량을 계산할 수 있는 수량예측모형(Ahn et al., 2014)을 결합하였다. 이 생물계절-수량 결합모형을 RCP8.5 기반의 남한 상세 기후시나리오(2000-2100)에 적용하여 7월 1일, 8월 1일, 9월 1일, 그리고 10월 1일 등 다양한 날짜에 배추를 정식할 경우 현재평년(2001-2010)과 미래평년(2011-2040, 2041-2070, 2071-2100)에 예상되는 수량성을 잠재수량에 대한 백분율로 표현하였다. 그 결과를 토대로 남한 전역을 810개 집수역으로 나누고 임의 집수역의 최적정식일을 사용자가 손쉽게 찾을 수 있는 시간 - 공간 - 수량 3차원 평가도표를 고안하였다. 이 방법은 미래 새로운 재배적지 탐색은 물론 기존 주산지에서 품종변경 없이 기후변화 적응이 가능한 작부체계 개발에도 유용할 것으로 기대된다. Planting date shift is one of the means of adapting to climate change in Kimchi Cabbage growers in major production areas in Korea. This study suggests a method to estimate the potential yield of Kimchi Cabbage based on daily temperature accumulation during the growth period from planting to maturity which is determined by a plant phenology model tuned to Kimchi Cabbage. The phenology model converts any changes in the thermal condition caused by the planting date shift into the heat unit accumulation during the growth period, which can be calculated from daily temperatures. The physiological maturity is estimated by applying this model to a variable development rate function depending either on growth or heading stage. The cabbage yield prediction model (Ahn et al., 2014) calculates the potential yield of summer cabbage by accumulating daily heat units for the growth period. We combined these two models and applied to the 1km resolution climate scenario (2000-2100) based on RCP8.5 for South Korea. Potential yields in the current normal year (2001-2010) and the future normal year (2011-2040, 2041-2070, and 2071-2100) were estimated for each grid cell with the planting dates of July 1, August 1, September 1, and October 1. Based on the results, we divided the whole South Korea into 810 watersheds, and devised a three - dimensional evaluation chart of the time - space - yield that enables the user to easily find the optimal planting date for a given watershed. This method is expected to be useful not only for exploring future new cultivation sites but also for developing cropping systems capable of adaptation to climate change without changing varieties in existing production areas.

고랭지 배추의 생장모의

Summer cabbages in an alpine area are very sensitive to the fluctuations in supply and demand. Yield variability due to weather conditions dictates the market fluctuations of cabbage price. This study reports an empirical relationship based on weather conditions to estimate the growth and harvestable biomass of cabbages, factors that are critical for supply of summer cabbages. Based on experimental results testing sowing date effects over the two years from 1997 to 1998, a logistic equation was parameterized to predict leaf area expansion of summer cabbages. This logistic model for leaf area expansion was then combined with an empirical allometric relationship to predict total biomass. The final equation for estimating fresh weight accumulation of Chinese cabbage is given by: Fresh weight =3500/(1+exp(5.175-1.153×(6/(1+exp(6.367-0.0064×PHU))))) Where PHU is potential heat units ( o C). The model performance was tested using weather data from 2003 to 2006 to predict fresh harvestable biomass. Overall the model performance was satisfactory with the correlation efficient ranging between 0.89 and 0.94 for each year.

계절별 절임배추의 품질 특성 비교

This study was carried to investigate the physicochemical and microbiological characteristics of seasonal salted-Kimchi cabbage order to provide basic data for optimal salting and storage condition of seasonal Kimchi cabbage. Generally, fall season samples had slightly higher pH and acidity value than the other seasonal salted Kimchi cabbage. The soluble solids content of spring, summer, fall and winter samples were 5.95%, 6.18%, 6.29% and 7.76%, respectively. The salt content of all the seasonal salted Kimchi cabbage samples were insignificant. The number of microbial bacteria in the summer samples were generally much more significant than spring and winter samples. There was no significant difference in the color of seasonal salted Kimchi cabbage. As for the texture properties, the firmest samples in the surface rupture test were the spring samples (force: 4.92 kg), and the hardest samples in the puncture test were the summer samples (force: 11.71 kg). In the correlation analysis of the quality characteristics of seasonal samples, the soluble solids content and hardness of the seasonal salted Kimchi cabbage was significantly correlated at 1% significance level. Also, in the principal component analysis, F1 and F2 were shown to explain 27.28% and 35.59% of the total variance (62.87%), respectively. The hierarchical cluster analysis of the quality characteristics of seasonal samples, the samples were divided into three groups: spring cabbage group, summer cabbage group and fall and winter cabbage group,.

Genetics of resistance to downy mildew in Brassica oleracea and breeding towards durable disease control for UK vegetable production

Downy mildew resistance was previously identified from screening a Brassica oleracea collection against two standard UK isolates of Hyaloperonospora parasitica. Sources of resistance were chosen from this material and developed further in this study by generating doubled haploid (DH) and inbred lines. Seedlings from the new lines were tested for resistance to a larger collection of H. parasitica isolates collected in 2001–2002 and 2007–2008 from the main broccoli and cauliflower production regions of the UK. Three lines (derived from borecole or summer cabbage) were broadly resistant to the pathogen isolates. Three of the remaining lines exhibited strong isolate‐specific resistance; several examples of weak or basal level of resistance to some isolates were observed. A new H. parasitica variant collected in 2008 was virulent in the broadly resistant lines, but was avirulent in a line with narrow specificity of resistance. The F2 and BC1 seedlings derived from outcrossing each of the three broadly resistant lines to susceptible broccoli and cauliflower lines segregated in a manner indicating that the resistance was controlled by a single dominant gene. No susceptibility was observed amongst F2 seedlings derived from intercrossing the three resistant lines, indicating that they all share the same or closely linked broad‐spectrum resistance gene(s). DH lines were produced from F1 plants, and resistant plants were further backcrossed to produce broccoli and cauliflower‐like lines that could be useful pre‐breeding material. A combination of resistance from lines with broad and narrow specificity is recommended for controlling downy mildew in UK brassica production.

English

An understanding of the causes of genotype x environment interaction can help in identifying traits and environments for better cultivar evaluation. The fact that head formation depends on other factors besides the cabbage accessions involved, makes it necessary to investigate accessions responses to agroecological growing conditions. Studied in the present paper was the stability of 21 cabbage accessions(10 cultivars and 11 F1-hybrids) with regard to head weight over three growing seasons. Joint analysis of variance revealed highly significant differences among the cabbage accessions, study years and accessions x year interactions. The parameter stability test showed that seven of the accessions (Kopenhaski and Elisa-F1 as early type; Tucana-F1 as summer type; Srpski melez, SG-3014, Ljubljanski and Rodeo-F1 as late type) significantly deviated from the regression line. Four of the seven accessions are cultivars and three F1-hybrids. These accessions had quite different regression coefficients around or above the value of one. Analysis of stability parameters for head weight showed the following accessions to be very stable: Copenhagen market (an early variety), Grenadier-F1 (a summer cabbage) and Ljubljanski (a late variety).   Key words: Stability, variety, cabbage, interaction, growing.

Adverse temperature tolerance induction in cabbage seed at germination stage

To investigate adverse temperature tolerance induction in summer and autoumn cabbage,changes in adverse temperature tolerance of pretreated cabbage seeds with different degrees of temperature during germination were investigated.Results show that the optimum germination temperature of cabbage seeds is 20 °C,and that germination vigor decreases remarkably when seeds germinate under above 35 °C or below 15 °C.Mild pretreatment temperature can greatly improve the germination ability of cabbage seed in high temperatures(35 °C).Minimum and maximum pretreatment temperatures are 10 °C and 30 °C respectively,optimal pretreatment time is 8 hours.Pretreatment lower temperatures of 5 °C and 10 °C improves seed vigor in high temperature(35 °C),while pretreatment higher temperatures of 25 °C and 30 °C improves seed vigor in low temperature(10 °C),implying that cabbage seeds have cross adaptation to heat and chilling stress.

Maturação e qualidade de sementes de repolho de verão sob condições tropicais

Avaliou-se o efeito do estádio de maturação dos frutos (síliquas) e da época de trilhagem sobre o potencial fisiológico de sementes de repolho, cultivar União. Em setembro de 2005 (200 dias após o transplantio), foi efetuada uma única colheita dos rácemos com síliquas em diferentes estádios de maturação, identificadas pelas colorações verde-escuro, verde-claro, arroxeada e bege. Estes estádios de maturação originaram sementes com coloração predominantemente verdes, castanho-claras, castanho-escuras e negras, respectivamente. Parte dos rácemos colhidos foi trilhada logo após a colheita e parte foi deixada em condições de laboratório, por uma semana, antes da trilhagem. O experimento foi conduzido no delineamento inteiramente casualizado, em esquema fatorial 4 x 2 (estádio de maturação das síliquas e época de trilhagem). As sementes foram submetidas a testes de grau de umidade, massa de 100 sementes, germinação, primeira contagem do teste de germinação, emergência de plântulas em casa de vegetação e envelhecimento acelerado. O potencial fisiológico das sementes variou entre os diferentes estádios de maturação das síliquas. Os resultados indicaram que os rácemos com síliquas de coloração verde-clara podem ser colhidos, desde que as sementes permaneçam no interior das síliquas por uma semana antes da trilhagem.

Modification and evaluation of the crop nitrogen model N_ABLE using Norwegian field data

Evaluation of the nitrogen simulation model, N_ABLE, was carried out using data from 10 Norwegian field experiments with winter and summer cabbage and onions grown on sandy and loamy soils in two different rainfall regions. The data was used to assess the benefits of modified growth and N recovery routines in the model. The modified growth equation (previously developed for lettuce) allows for physiological factors to alter the underlying pattern of growth from a J-shaped to an S-shaped curve independently of both temperature and N supply. Simulated dry weights for both winter cabbages and onions (both exhibiting a sigmoid growth curve) were significantly improved using the modified growth equation, provided adjustments were made for the use of onion sets instead of seeds. In addition, the modified growth equation accurately simulates a J-shaped curve exhibited by summer cabbage and other summer vegetables. Tests are also made of modifications to the original soil-N recovery equation to correct for inconsistencies caused by a discontinuity in the N recovery function. The modified soil–N equation was found to give a better description of the relationships between the decrease of N recovery with the increase in fertiliser-N level.

キャベツの黒すす病に対する感受性の品種間差異

Cabbage plug seedling has been popular in Japan and Alternaria sooty spot causes severe damage on them. Young seedlings of 20 cabbage cultivars were sprayed with conidial suspension of the pathogen and their susceptibilities to the disease were evaluated by severity of the symptom, which appeared in the cotyledons one week later. “Kagayaki” was the most resistant among them, but not complete. Most of the susceptible cultivars were resistant to Fusarium wilt, and many of the cultivars of spring and early summer cabbage were unstable in symptom severity of Alternaria sooty spot.

Avaliação de repolhos de verão na várzea do estado do Amazonas

Um experimento de campo foi conduzido na Embrapa Amazônia Ocidental, em Iranduba, AM, de setembro a dezembro de 1995, para avaliar nove cultivares de repolho de verão, entre comerciais (híbridos Master, Shutoku, Saikô, Sooshu - testemunha e a variedade de polinização aberta União) e experimentais (híbridos XPH - 5786, XPH - 5787, XPH - 5904 e XPH - 5909), nas condições do ecossistema de várzea (solo Gley Pouco Húmico). O delineamento experimental foi blocos ao acaso, com quatro repetições. A parcela constituiu-se de quatro linhas de cinco plantas no espaçamento de 0,80 m x 0,40 m. Como fertilizantes foram utilizados apenas o bórax e a uréia, devido aos bons níveis naturais de outros nutrientes dos solos de várzea. As irrigações e os tratos culturais foram executados conforme as necessidades da cultura. Os maiores rendimentos por parcela foram dos híbridos Saikô (12,5 kg) e Sooshu (15,0 kg) e os menores do híbrido Master (7,0 kg) e da cv. União (6,0 kg). As cabeças mais pesadas foram as dos híbridos Sooshu (810,6 g), Shutoku (719,1 g) e Saikô (698,0 g). Destacaram-se como mais compactos os híbridos Saikô e Shutoku. As cabeças foram levemente achatadas para os híbridos Saikô e Shutoku, formato preferido comercialmente, e achatadas para o híbrido Sooshu; as demais cultivares produziram cabeças levemente alongadas. Para a profundidade do coração, (comprimento do coração/diâmetro longitudinal), apenas os híbridos Master e Shutoku tiveram valores depreciativos (0,62 e 0,64), respectivamente). Os híbridos Sooshu, Shutoku, Saikô e a cv. União foram os mais precoces e o híbrido XPH-5787 o mais tardio. Concluiu-se que o híbrido Saikô apresentou o conjunto mais consistente de características desejáveis, expressando boa adaptação às condições edafoclimáticas de várzea, podendo ser testado em níveis mais extensivos nesse ecossistema

Características de repolhos de verão em ecossistema de terra firme do Amazonas.

Um experimento de campo foi conduzido na Embrapa Amazô nia Ocidental, município de Manaus, AM, de setembro a dezembro de 1995, em solo do tipo Latossolo Amarelo muito argiloso, ecossistema de terra firme, para avaliar diferentes repolhos de ve rão: União, Master, Shutoku, Astrus, Saikô, Sooshu (testemunha), Saturno, XPH 5786, XPH 5787, XPH 5904 e XPH 5909. Os seis primeiros são comerciais e os restantes híbridos experimentais. O delineamento experimental foi de blocos ao acaso com quatro repe tições e parcelas de 20 plantas no espaçamento 0,80 m x 0,40 m. Realizou-se adubação orgânica e química, bem como os tratos cul turais necessários. Os híbridos XPH 5787, XPH 5909, XPH 5904, Saturno, Sooshu, Saikô, Astrus e Shutoku apresentaram as cabeças mais pesadas (799,03 g a 1119,54 g). Foram mais produtivos os hí bridos XPH 5787, XPH 5909, XPH 5904, Saturno, Sooshu, Saikô e Astrus, cujas produções por parcela variaram de 14,50 kg a 20,73 kg. As cabeças mais compactas foram produzidas pelos híbridos Shutoku, Astrus, Saikô, XPH 5786, XPH 5909 e XPH 5787. O hí brido XPH 5909 foi o de menor profundidade do coração (relação C/D de 0,51). Os híbridos Master, XPH 5786 e XPH 5787 forma ram cabeças levemente alongadas, de pouca aceitação comercial. O híbrido Sooshu foi o mais precoce com ciclo vegetativo de 60 dias. Concluiu-se que, dentre as cultivares comerciais, os híbridos Saikô e Astrus podem ser testados em níveis mais extensivos, em ecossistema de terra firme, para uso alternativo à testemunha. Os híbridos experimentais XPH 5909 e XPH 5787, que tiveram boa produtividade, mostraram incidência de cabeças com formação in terna atípica e foram mais tardios que a testemunha e os dois primei ros (Saikô e Astrus), o que levou à não indicação dos mesmos.

Dynamic model for the effects of K fertilizer on crop growth, K‐uptake and soil‐K in arable cropping. 2. Field test of the model

Abstract. The validity of the model described in Greenwood & Karpinets (1997) was tested against the results of single year, multi level K fertilizer experiments. Measurements of plant mass, %K in the plant and K activity ratio in soil had been made at harvest and at intervals during the growing season on spring wheat, summer cabbage and turnips. Reasonably good agreement was obtained between these measurements and simulated values when the two ‘crop’ parameters (defining the dependence of critical and maximum possible %K on plant mass) were adjusted for each crop. Also good agreement was generally obtained for plant weight and plant %K at harvest in less detailed experiments on 10 other crops. Values of the two ‘crop’ parameters for 12 of the crops were strongly correlated with one another suggesting that a single ‘crop’ parameter may be all that is required to define most inter‐species differences in plant‐K demand.Simulations with the model indicate that, in central England, no response of 10 crops to K fertilizer would be likely on soils containing more than 170 mg of 1 M ammonium nitrate extractable‐K/kg of soil and having clay contents of between 15 and 45%. Shortcomings of the model and opportunities for advance are discussed.A simplified version of the model runs on the Internet at: http://www.qpais.co.uk/moda‐djg/potass.htm

Potential for nitrate leaching from different land uses in the Pukekohe area

Nitrogen balances (inputs minus outputs) were calculated for 5 dairy farms, 5 orchards and a range of crops. All the balances were positive, i.e., surplus N was present and a proportion of this N will eventually reach the groundwater as nitrate. On a per ha basis, the greatest N surplus was from early potatoes > winter cabbage, winter lettuce and squash > dairying, kiwifruit, summer cabbage and summer lettuce > pumpkins, onions and main crop potatoes > dry stock farming. The area in each activity was multiplied by the surplus N factor to obtain the potential contribution of N to groundwater in the Pukekohe area. Early potatoes (217 t N), contribute much more than onions (105 t N), dairying (59 t N) or dry stock farming (57 t N). Other activities contributed < 30 t N each. Winter crops had higher surplus N levels than the same crop grown in summer because winter crops had higher fertiliser N inputs and lower crop off-take of N. Management practices contributing to the N surpluses include high rates of N fertiliser used on some crops; a long history of cultivation, which has reduced soil organic matter contents and the ability of these soils to immobilise mineral N; and nil to intermittent use of cover crops to retain N in the topsoil. Keywords: aquifers, dairying, fertiliser, groundwater, land use, management, nitrate, nitrogen balance, nitrate leaching, vegetables.

Nitrogen fertilizer value of activated sewage derived protein: Effect of environment and nitrification inhibitor on NO 3 - release, soil microbial activity and yield of summer cabbage

Yield response of summer cabbage (Brassica oleracea varcapitata cv. Hispi F1) to N applied as organic (activated sewage sludge derived protein [Protox] and dried blood) and inorganic (ammonium nitrate, ammonium sulphate, sodium nitrate and urea) fertilizers was compared in relation to the N availability characteristics of the materials. Effects of the nitrification inhibitor dicyandiamide (DCD) on N release, crop yield and N status were also assessed. In addition CO2 efflux was measured from amended soil to determine effects of fertilizer application on soil microbial activity. The organic N sources were mineralized quickly on application to soil and exhibited similar patterns of NH4-N depletion and NO3-N accumulation as functions of thermal-time as with mineral fertilizers. However, the yield response to organic N was marginally smaller (though not significantly) compared with mineral forms; probably because less N was released to the crop. This was reflected in smaller total N concentrations and N recoveries in plants supplied with organic fertilizer. Applied DCD increased the thermal-time for complete nitrification of NH4-N sources and raised the total N content of the crop, but had no overall effect on crop growth. In contrast to inorganic N sources which generally reduced CO2 efflux from soil, application of protein-based fertilizers increased the rate of soil microbial activity directly by raising substrate availability. Sewage sludge derived protein provided an effective alternative to mineral fertilizers for the nutrition of summer cabbage whilst minimising stress of the soil environment which may occur following the application of conventional forms of inorganic N to the soil.

Delia floralis . [Distribution map

Abstract A new distribution map is provided for Delia floralis (Fallén) Diptera: Anthomyiidae Turnip root fly, summer cabbage fly. Attacks Brassica spp., swede, cabbage, cauliflower, calabrese, Chinese cabbage, turnip, radish, wallflower, rapeseed (canola) Information is given on the geographical distribution in EUROPE, Denmark, Finland, Germany, West Hungary, Italy, Norway, Sweden, Switzerland, United Kingdom, USSR, Byelorussian SSR, Estonian SSR, Kazakh SSR, Latvian SSR, Moldavian SSR, Russian, SFSR, Kamchatka region, Leningrad region, Pushkin area, Ukraine, Uzbekistan, ASIA, China, Japan, Mongolia, NORTH AMERICA, Canada, Alberta, Manitoba, Newfoundland, Saskatchewan, USA, Alaska.

Population fluctuations of the diamondback moth, Plutella xylostella (L.) on cabbages in Bacillus thuringiensis sprayed and non sprayed plots and factors affecting within‐generation survival of immatures

SummaryThe population fluctuations and within‐generation survival of immatures stages of the diamondback moth, Plutella xylostella on summer cabbages, were examined in unsprayed plots in 1984 and 1985 and in plots sprayed with two formulations of Bacillus thuringiensis in 1985. There was two distincy generations per crop and no noticeable difference in population fluctuations were observed in unsprayed plots between years. There was distinct difference between unsprayed and sprayed plots in 1985, from the larval period onwards. However, the survivorship patterns in all plots in both years were a Type 2 based onDeevey's (1947) classification. Life table studies showed that there was essentially no difference in the mortality agents acting on each of the stages except for numerical differences in the within‐generation mortality rates. The major mortality rates during the egg stage were the parasitoid, Trichogramma spp. and unknown factors including rainfall; in the larval 1 stage was unknown mortality; in the larval 2 stage was the parasitoid, Apanteles plutellae and during the pupal stage was unknown mortality and parasitoid, Diadromus subtilicornis. Adult mortality was determined for generation 2. It was relatively higher in the unsprayed plots compared to the B. thuringiensis sprayed plots. The contribution of abiotic factors such as rainfall and temperature, and biotic factors such as parasitoids and predators in determining within‐generation population levels and the fluctuation of populations on cabbage were discussed.