进口大豆中杂草籽截获规律及检疫要点

[目的]研究归纳进口大豆杂草籽截获规律,提高口岸杂草籽截获的目的性.[方法]根据杂草籽日常截获及鉴定情况,结合山东口岸截获的实际情况进行分析总结.[结果]口岸截获杂草籽主要种类数是88种,主要集中于禾本科、菊科、旋花科、豆科、蓼科、锦葵科、苋科、大戟科、藜科9个科;检出检疫性杂草籽,共计48种,主要集中在菊科、禾本科、...     

进境曼陀罗超标大豆过筛处理的方法

通过在大豆加工设备中添加筛网来去除大豆中携带的曼陀罗籽.在加工过程中在两组筛网处设置4个取样点并在统一的时间取样,通过对4个位置所取大豆样品中曼陀罗含量的分析,得出过筛处理的曼陀罗去除效率,结果证明过筛处理是一种有效的去除大豆中携带超标曼陀罗籽的方法.     

钦州口岸进口大豆检出杂草情况分析

本文根据钦州口岸2006～2008年进口大豆中检出杂草的情况,对来自美国、巴西、阿根廷的大豆的杂草检出结果进行了汇总和分析,检疫性杂草检出率为100%,美国大豆疫情最严重,不同来源国大豆中杂草种类不尽相同.     

进口大豆杂草检疫刍议

目前,我国进口大豆量不断增加,从进口大豆检疫情况看,杂草疫情复杂,如何加强对进口原粮的检疫与加工处理的监管,严防外来杂草传入传播,是急待解决的重要问题.     

张家港口岸进口大豆的疫情分析及检疫监管对策

自1996年以来,张家港动植物检疫局检疫了来自美国、巴西等国家的进口大豆100余万ｔ,截获了36种杂草和18种病原菌,其中包括大豆疫霉、假高粱等植物危险性有害生物,因此加强对进口大豆的检疫检验并做好后续检疫监管工作显得尤为必要。本文通过对我局进口大豆携带杂草、病原...     

进境美国大豆杂草和杂质含量研究

自装载美国大豆的外轮货舱中取样,研究进口美国大豆携带杂草和杂质的含量关系:取样量为5 kg/1 000 t,是能反映进口大豆中杂草和杂质含量关系的最低取样量;把进口美国大豆杂质含量划分为1.5%、1.5%~2.0%和2.0%3个区间,其携带杂草含量和种类与杂质含量呈显著的正相关;进口大豆中携带杂草含量高的,检出频率也相对高,但检出的杂草总种类数少于杂草含量低的;杂草含量低的,检出频率也相对低,但检出的杂草总种类数多于杂草含量高的。     

广州新沙港对进口大豆的检验检疫和监管

广州新沙港自 2 0 0 1年 8月至 2 0 0 2年 8月对进境的非种用大豆进行了有效的检验检疫与监管。1　检验检疫情况1 1　检疫与疫情一年来 ,在从美国、巴西、阿根廷进境的8批次约 3 2万ｔ大豆中截获杂草 2 7种 ,其中有二类危险性杂草假高粱 8批次 ,黑高粱 4批次。对危险性杂草超标的情况 ,均按规定出证并对外索赔。1 2　品质检验从美国、巴西和阿根廷进口的大豆分别进行水分、杂质、破碎粒、损伤总量、热损伤粒、油分、蛋白质的检验 ;此外 ,对美国进口大豆还进行异色粒和容重检测。其中从巴西进口的 1批大豆的杂质检测结果为 2 1 1 %,油…     

进口大豆中杂草种子含量检测及分析

自2000年以来,进口浸油用大豆成为秦皇岛口岸进口粮的主要部分.大豆分别来自美国、巴西、阿根廷.从2001年起,我们对秦皇岛口岸进口的22条船约89万t大豆进行了杂草种子含量测定,其结果供进口大豆检验检疫及风险分析、进口商选购高品质的大豆参考.     

假高粱在大轮散装进口大豆中的分布情况

随着我国近年来进口粮数量的增加,许多口岸经常面临检查进口粮是否携带假高粱以及假高粱是否超标出证的问题。本文统计分析了1996年至2000年6月份张家港口岸大轮散装进口大豆中假高粱分布情况,旨在为今后的合理取样检查提供参考。1　进口大豆概况张家港口岸近年来每年进口大豆100万ｔ左右,进口国主要是美国、巴西和阿根廷等3个国家。每船进口大豆的数量在1～5万ｔ不等,每船取样3～5次。从1996年至2000年6月,共检验检疫了71批(船)进口大豆,发现假高粱51批(船),其中假高粱超标23批(船),对外出证23份,并有效地做好了疫粮的监管工作。2　不同国…     

青岛口岸进境大豆携带危险性杂草的风险分析

对2000年青岛口岸进境大豆中携带杂草籽的种类、数量、截获率和超标情况进行风险分析 ,提出了口岸检疫、大豆运输流向及疫情处理等方面的风险管理措施。     

进境美国高粱携带杂草种子萌发率测定

收集并整理2014~2016年从黄埔和南沙口岸进境美国高粱中截获的杂草种子,对截获频次进行统计,并对截获频次较高的9种检疫性杂草、14种非检疫性杂草进行萌发试验,结果表明,供试杂草种子几乎均能萌发,且萌发率较高,如长芒苋和裂叶牵牛萌发率达58%以上、糙果苋19.17%、假高粱和豚草的萌发率也达到7.50%和5.00%。因此要重视美国高粱中携带的杂草种子检疫以及杂草监测工作,防止这些杂草种子的定殖传播。     

种菟丝子种子数学形态特征的初步研究

本研究基于数字图像处理与分析技术,首次用FeatureExtract数学形态特征提取软件获取了3种菟丝子图像的13项数学形态特征值,并做了方差分析和聚类分析。结果表明,该技术可应用于杂草种子快速鉴定。同时提出对方法的改进建议,为最终实现杂草种子的快速鉴定奠定了基础。     

Potential of weed seedbanks for managing weeds: a review of recent New Zealand research

Weed seedbanks are the primary source of weeds in cultivated soils. Some knowledge of the weed seedbank may therefore be appropriate for integrated weed management programs. It would also be very useful in planning herbicide programs and reducing the total herbicide use. However, a number of problems are inherent in the estimation of the seedbank size for arable weeds that usually have annual life cycles. In a long-term research project we have investigated the dynamics of weed seedbanks in corn fields for the past 8 years. Specific studies have included (i) developing cheap and efficient methods for estimating the weed seedbank; (ii) developing guidelines for efficient soil sampling (including the number and size of samples); (iii) influence of cultivation methods on weed seed distribution; (iv) mapping the spatial variability of the seedbank; (v) estimating the rate of seedbank decline for certain weed species; and (vi) assessing the potential of using the weed seed content in the soil to predict future weed problems. This paper reviews and summarizes the results of our research on the above aspects. The strong correlation between seedlings emerged in the greenhouse and seeds extracted in the laboratory for the most abundant weed species has demonstrated the potential for using the weed seed content of the soil to predict future weed infestations. The next step is to establish correlations with field emergence under commercial conditions using the sampling guidelines developed in our studies. Subsequently, we aim to offer the weed seedbank estimation as a commercial service to farmers for planning the most appropriate weed management options.     

The efficiency of a vacuum device for estimating soil-surface seed abundance on lowland farms

Accurate sampling methods for estimating soil-surface seed abundance in agro-ecosystems are vital for understanding arable plant population dynamics, as well as quantifying seed availability as a food resource for farmland birds, mammals and arthropods. We tested the sampling efficiency of a portable, petroleum spirit powered leaf blower-vacuum in recovering four different seed size classes on the soil-surface of seven lowland farm habitats. Vacuum sampler efficiency was dependent on seed size, habitat type and exposure of seeds to environmental conditions. Larger seeds were more readily recovered and overall seed recovery was consistently higher on habitats with low vegetation cover, such as newly-sown cereal fields. We discuss the limitations of the device, but commend its use with correction factors to estimate soil-surface seed abundance in agricultural habitats. This study highlights the potential biases when estimating soil-surface seed abundance, the importance of correcting such biases and the need for better sampling techniques for weed science.     

Dependence of weed flora on the active soil seedbank

Previous studies have shown that reliable predictions of the above-ground weed flora may not be obtainable by using the total number of seeds in the seedbank. The purpose of this study was to determine if the actual weed flora depends on the active soil seedbank (seeds that are germinable in the spring). In the 1995 growing season, seedling emergence was monitored within permanent quadrats established in a field. Soil cores taken from the same field were also monitored for seedling emergence in a greenhouse to estimate the number of seeds in the active soil seedbank. Significant positive relationships were observed between the above two variables based on either total weed flora or individual weed species commonly found in south-western Ontario, Canada. For relatively large-seeded species, the relationship held with a sampling depth up to 15 cm below the soil surface. For small-seeded species, a shallow sampling depth (0–7·5 cm) generated better results than deeper sampling (0–15 cm). In general, 3–7% of the seeds in the active soil seedbank were capable of producing seedlings in the field. The results suggest that the level of weed infestation in a growing season may be predicted using seeds in the active soil seedbank.     

Evaluation of sampling methods and assessment of the sample size to estimate the weed seedbank in soil, taking into account spatial variability

As field sampling is time consuming, it is necessary to develop efficient sampling techniques to obtain accurate estimates of the weed seedbank in soil. The relative efficiency between sampling schemes depends on the spatial variability in weed seed density across agricultural fields. Spatial variability of the weed seed density was characterized by theoretical correlograms. A systematic sampling (square grill) scheme was considered and it was found that, taking into account spatial variability, this sampling scheme was more efficient than simple random sampling. As a result, the sample size can be reduced in comparison with that given in previous studies, where spatial correlation was ignored. The reduction depends on the correlation structure defined as a function of the ratio, τ, between the nugget effect and the sill of the variogram. The maximum reduction of the sample size, without loss of either precision or confidence level corresponds to the case where there is no nugget effect, τ = 0. The opposite extreme case, where the reduction is nil, corresponds to the case of a pure nugget effect τ = 1. The abaci based on given expressions are provided to determine the sample size in species whose spatial pattern can be fitted either to a Poisson or to a negative binomial distribution.     

Strategy of Echinochloa oryzicola Vasing. for survival in flooded rice

Echinochloa oryzicola Vasing. (= Echinochloa phyllopogon Stapf ex Kessenko) is an obligate weed with an elaborated survival strategy in the flooded rice of Japan. In this review various adaptive characters of the weed, which comprise the survival strategy, are discussed through the life cycle. The weed is distributed only in flooded rice. Seeds (spikelets) buried in the soil exhibit annual cycles between dormant and non‐dormant state, and non‐dormant seeds recurrently appear in spring when rice growers start to prepare seedling beds and fields for rice transplanting. The non‐dormant seeds have unique characters metabolically adapted to submerged conditions to germinate and grow by the anaerobic respiration through alcohol fermentation. The weed has seemingly perfect mimicry of the rice plants throughout its development from seedling to heading, by which the weed escapes from manual weeding. In a rice paddy, the weed starts heading coincidentally with the rice plants at the period when the growers are reluctant to walk in the rice paddy to weed. Irrespective of plant height of the rice cultivar, the weed develops a few upper leaves above the rice canopy during the heading period of rice. This phenotypic plasticity of E. oryzicola in plant height is one of the characters conferring its competitive aggressiveness in flooded rice. When weeding is begun again after heading, the dormant weed seeds escape weeding by shattering and join the soil seedbank. The dormant seeds express the gene of an enzyme catalyzing ATP synthesis through the mitochondrial oxidative phosphorylation more abundantly, and have larger oxygen absorption and enzyme activity of the aerobic respiration than the non‐dormant seeds, suggesting that the dormant seeds maintain viability by the conventional aerobic respiration in the paddy soil drained from rice harvesting in fall to the next early spring. The various adaptive characters comprising the survival strategy of E. oryzicola in flooded rice consist of those inherited from the wild progenitor and those selected by the crop cultivation pressure. It is suggested that both the mimicry of the weed and the heading coincident with the rice plants have been acquired by the large selection pressure of frequent weeding, which has been done over the past hundred years. However, today, the manual weeding is substituted with herbicides, which cannot detect the mimicry and heading photoperiodic sensitivity. As a result, the dominant species of Echinochloa weeds in flooded rice is changing from E. oryzicola to Echinochloa crus‐galli var. crus‐galli that has neither mimicry nor photoperiodic sensitivity synchronizing to that of rice, but is more competitive against rice.     

Factors impacting the detection of weed seed contaminants in seed lots

BACKGROUND

The setting and following of phytosanitary standards for weed seeds can lessen the impacts of weeds on agriculture. Standards adopted by seed companies, laboratories and regulators ensure the contamination rates do not exceed some thresholds. Globally sample size standards are set based on the amount needed to obtain a contaminant in a random sample of the seed lot, not detectability. New Zealand requires a 95% confidence that the maximum pest limit of 0.01% of quarantine weed seed contamination is not exceeded in an imported seed lot. We examined 24 samples each containing approximately 150 000 seeds of either perennial ryegrass (12 samples) or white clover seeds (12 samples) that were then spiked with seeds (contaminants) from 12 non-crop species (3–8 seeds of each). We considered factors that may impact detection rates: shape, color, size, and texture relative to the crop, and technician (including a commercial seed laboratory).

RESULTS

A linear mixed model fitted to the data indicated significant observer, crop, and seed color, shape, and size effects on detection. Detectability increased by 20% ± 7.7 (± standard error) when seeds had a distinct shape or color (28% ± 8.1), or were larger (23% ± 8.7) rather than smaller, relative to the crop. Commercial laboratory identifications were usually correct at the level of genus, and species for common weeds, but some misidentifications occurred.

CONCLUSION

Sample sizes for border inspections should be based on detectability of regulated weed seeds in the crop in combination with weed risk for the crop and location. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Sheep as vectors for branched broomrape (Orobanche ramosa subsp. mutelii [F.W. Schultz] Cout.) seed dispersal

Sheep can be vectors for the long‐distance dispersal of weeds when seed becomes attached and retained in wool or survives the gastrointestinal tract. This study aimed to determine an appropriate quarantine period for sheep that minimized the risk of the long‐distance dispersal of the seeds of branched broomrape (Orobanche ramosa L. subsp. mutelii [F.W. Shultz] Cout.), a parasitic weed. Experiments with penned sheep found that the seeds that were placed on the soil surface adhered to the wool on the thigh and belly of the sheep, with most of the seeds attaching to the feet. Most of the seeds that were applied to the belly and thigh wool detached within 2 days, although a small proportion was present after 7 days. The seeds that were introduced to the digestive tract via drenching had a peak voidance 2 days later and no seed was detected on Day 8. It is suggested that a 7 day quarantine period for sheep would be sufficient in order to reduce the risk of the internal transport of seed to acceptable levels, but a small risk of the external transport of seed on the fleece remains.