甜瓜黑点根腐病菌生物学特性及其对药剂敏感性测定

为明确甜瓜黑点根腐病的发生和流行规律及有效防治方法,在不同培养基、碳源、氮源、温度、pH等培养条件下,测定甜瓜黑点根腐病菌的生物学特性及其对多种瓜类作物致病性,并采用菌丝生长速率法测定菌株对不同药剂的敏感性。结果表明,甜瓜黑点根腐病菌MC8菌丝生长的适宜培养基为马铃薯蔗糖培养基、燕麦粉琼脂和马铃薯葡萄糖琼脂培养基,马铃薯蔗糖培养基、燕麦粉琼脂和玉米琼脂粉这3种培养基可产生子囊壳;碳源和氮源对菌丝生长无明显促进作用,但乳糖可显著促进子囊壳产生,该发现为国内外首次报道;MC8菌丝生长的适宜pH为5～7,菌丝和子囊壳生长最适温度为30℃。致病力试验结果显示MC8菌株可侵染西瓜、甜瓜、南瓜和葫芦多种瓜类作物。咪酰胺和嘧菌酯在PDA上对瓜类黑点根腐病菌的菌丝生长有较好的抑制效果。     

墨西哥北部首次报道由甜瓜黑点根腐病菌引起的甜瓜病害

2010和2011年,在墨西哥北部Comarca Lagunera地区4个商业园中,有3个园的甜瓜植物在收获之前表现出叶子和枝蔓萎蔫症状。田间发病率在30%左右。发病植株在根部表现为坏死斑及次生根减少,以     

豌豆脚腐病菌

豌豆脚腐病菌(Phoma pinodella(L.K.Jones)Morgan-Jones&K.B.Burch)是我国进境植物检疫性有害生物,主要引起豌豆的脚腐病,目前在我国无分布。本文主要从地理分布、寄主范围、症状及危害、形态特征、生物学习性、检疫鉴定方法、防治措施等方面作一介绍,为防范其入侵提供理论基础。     

中国口岸首次截获外来有害杂草——胀果苋

胀果苋(Amaranthus deflexus L.)为一年生或短期多年生植物,广泛分布于热带、亚热带与暖温带地区,但在中国尚未分布。由于胀果苋为恶性杂草,对农田、果园、路旁、园林绿化等危害严重。福建出入境检验检疫局首次截获胀果苋,系我国口岸首次截获该种外来杂草。本文根据截获的胀果苋种子及栽种植株,详细对其形态特征进行了描述;并根据资料,介绍了胀果苋的分类地位、地理分布、生物学与危害性,为口岸胀果苋的鉴定识别提供参考。     

我国首次截获的一种危险性害虫--暗条豆象

2003年5月,江阴检验检疫局检疫人员对非洲籍的"星光丸"废旧船舶进行检疫.由于该船即将作为再生资源被利用,且曾往返世界各国多次,考虑到其在世界各国购买食品,疫情会相对复杂.为防止食品舱中的疫情在该船拆解过程中扩散,故检疫人员对该船食品舱的检疫相当仔细认真.在食品舱货架处发现有豆象科成虫,采样后经国家质检总局动植物检疫实验所张生芳研究员鉴定为一种重要的检疫性害虫--暗条豆象Bruchidius atrolineatus(Pic).现将该虫的形态特征、分布等情况介绍如下.     

西瓜绵腐病菌生物学特性研究

本文针对辽宁省西瓜生产上近年趋重发生的绵腐病,通过病原菌形态特征观察、柯赫氏法则证病试验、rDNA-ITS序列测定及分析,确定其致病菌为瓜果腐霉(Pythium a phanidermatum);并对该病原菌的主要生物学特性进行了研究.试验结果表明:菌丝在黄瓜煎汁培养基、蔗糖培养基、硫酸铵、甘氨酸培养基中生长最适;其生长最适温度35℃,最适pH为6～8;光照对菌丝生长影响较小;菌丝致死温度为51℃,10 min.产生孢子囊以菠菜煎汁培养基为最适,在麦芽糖、硝酸钾培养基中孢子囊产生量最大;产生孢子囊的最适温度为25℃、最适pH为8;光照培养产生孢子囊数量最多.     

棉花根腐病菌鉴定特征的快速培养条件

系统地研究棉根腐病菌的形态学特征及生理生化特性 ,总结出适用于检验检疫部门之快速、准确的鉴定方法 ,即无性器官快速形成条件。实验表明 ,病菌在 2 8℃ ,经过改进的No .70培养基上可生长出易于快速鉴定的典型的无性器官。     

寒地水稻秆腐菌核病菌的生物学研究

研究结果表明,水稻秆腐菌核病菌可利用多种碳源和氮源,碳源以可溶性淀粉最好,氮源以酒石酸铵最好,混合碳源(蔗糖+鼠李糖)对病菌菌丝生长有促进作用,比单独蔗糖和鼠李糖生长的好;病菌能在多种天然培养基上生长并形成菌核;菌丝在碳氮比为60∶1的培养基上生长最好;生长物质VB₆+肌醇、VB₆+谷氨酰胺等11个组合对菌丝生长有促进作用;微量元素中亚铁、锰和硼对菌丝生长有抑制作用;液体培养中以Czapek培养基生长最好,但不利于菌核的形成;菌核在15～35℃均可萌发,最适温度为30℃;菌核在0.05%葡萄糖溶液、蒸馏水、水琼脂上均可萌发,以0.05%葡萄糖溶液萌发最好。     

柑橘黑色蒂腐病菌的分离鉴定及生物学特性

从自然发病的柑橘果实表面分离出柑橘黑色蒂腐病菌(Diplodia natalensis Evans),对其生物学特性研究的结果表明:不同培养基对菌落形态、菌丝生长速率及产孢量都有很大影响,其中以马铃薯蔗糖培养基菌丝生长旺盛,生长速度最快,产孢量最大。病原菌适宜的生长及产孢温度为25~30℃,最适温度为30℃;光照条件对病菌的生长及产孢没有显著的影响;病菌的致死温度在75℃左右,在测试的常用化学药剂中,以咪鲜胺对其抑制效果最好。     

我国首次截获检疫性有害生物——大洋臀纹粉蚧

沈阳出入境检验检疫局机场办事处于2008年5月从旅客携带的水果中截获了检疫性害虫一大洋臀纹粉蚧Planococcus minor(Maskell).该害虫在我国大陆尚未分布,应严防其传入.文章介绍了其形态特征、寄主、生物学特性及基本防治策略.     

甘肃酒泉发现坎诺单孢菌引起的甜瓜倒秧

2018年7月中旬在甘肃省酒泉市金塔县, 甜瓜成熟前10~20 d, 一些田块出现了严重的倒秧, 从罹病植株的褐腐根上分离到坎诺单孢菌Monosporascus cannonballus, 病株分出率达76.9%。致病性测定结果显示:在试验条件下(25℃±3℃), 菌株TG-84对甜瓜(品种:‘86-1’)的致病性强, 出苗后13 d, 倒苗率达80%。     

Effect of Irrigation Regimes on Disease Expression in Melon Plants Infected with Monosporascus cannonballus

The effect of irrigation regimes on disease expression in melon plants infected with Monosporascus cannonballuswas studied during two summer growing seasons (1998 and 1999) in the Arava region of southern Israel. Less frequent and reduced irrigation postponed the onset of plant collapse and lowered disease incidence. Delaying disease development in infested fields by reducing irrigation frequency allowed crop harvest before plant collapse. However, reduced irrigation regimes reduced yields, as shown in methyl bromide fumigated plots. Fruits from melon plants grown under reduced irrigation in the infested plots were also of lower quality due to water shortage. The delay in plant collapse under the reduced irrigation treatments was attributed to a combined effect of reduced fruit load and the development of a deeper root system, which could support the increased water demand of the mature, fruiting plant.     

Effect of soil temperature on disease development in melon plants infected by Monosporascus cannonballus

The effect of soil temperature on melon collapse induced by Monosporascus cannonballus was studied in the laboratory and in the field. In the laboratory, ascospore germination and hyphal penetration into melon roots were enhanced by increasing the temperature from 20 to 32°C. The optimum temperature for mycelial growth of five isolates of M. cannonballus was 30°C. In the field, the effect of temperature was studied in experiments conducted during the winter and autumn cropping seasons from 1995 to 1998. Disease progress was much faster in the autumn than in the winter crop seasons. Disease incidence reached 100% in the three consecutive autumn seasons studied. In the winter seasons, however, planting date influenced disease incidence. Early planting, at the beginning of January, resulted in a low disease incidence (6–26%, 125 days after planting), whereas planting at the end of January resulted in higher disease incidence (72–88%, 95–119 days after planting). In plots in which the soil was artificially heated to 35°C during the winter season, disease incidence reached 85%, as in the autumn season. Plants grown during the winter in unheated soil, or in artificially heated soil disinfected with methyl bromide, did not collapse. Root colonization by the pathogen was higher in the autumn and in heated soil than in the winter season in nonheated soil. Fifty per cent of root segments were colonized 35, 42 and 67 days after planting in the winter-heated, autumn and winter-unheated plots, respectively. A high correlation was found between soil temperatures above 20°C during the first 30 days after planting and disease severity. It is suggested that soil temperature during the early stages of plant development is an important factor in disease development and the expression of melon collapse caused by M. cannonballus.     

Sanitation practices that inhibit reproduction of Monosporascus cannonballus in melon roots left in the field after crop termination

Ascospores of Monosporascus cannonballus function as primary inoculum for infection of melon roots. Previous studies demonstrated that pathogen reproduction (i.e. ascospore production) occurs on infected melon roots primarily after the crop has been terminated. Therefore, the key to maintaining low soil population densities of the pathogen is to destroy the hyphae of the pathogen in infected roots as soon as possible after crop termination, thereby inhibiting ascospore production. Results from a 3-year field study demonstrated that, relative to the nontreated controls, an immediate postharvest application of metam sodium (applied via the drip irrigation system at 187 L ha⁻¹) or cultivation (which lifts roots onto the surface of the soil for rapid desiccation) significantly inhibited pathogen reproduction in infected melon roots, as shown by the number of roots subsequently bearing perithecia. Additionally, ascospore populations in plots that received either the metam sodium or cultivation treatment were significantly lower ( P  < 0·05) than populations in the nontreated control plots at the end of the 3-year study. These results demonstrated the efficacy of these postharvest treatments in the inhibition of pathogen reproduction and retardation of inoculum build-up in soil.     

Effect of water potential on mycelial growth and perithecial production of Monosporascus cannonballus in vitro

The effects of osmotic water potential (Ψ_s) on mycelial growth and perithecial production of Monosporascus cannonballus , the cause of root rot and vine decline of melons, were examined at 25°C on potato dextrose agar (PDA) amended with KCl, NaCl or sucrose. Patterns of the growth responses of four isolates to decreasing Ψ_s were similar for each of the osmotica. Compared with growth on nonamended PDA (−0·3 MPa), growth of all isolates increased as Ψ_s was reduced to −0·8 MPa. Maximum growth occurred at Ψ_s values of −0·6 to −0·8 MPa. Growth was not reduced below that on nonamended PDA until Ψ_s was reduced to −1·8 MPa, and a 50% reduction in growth did not occur until Ψ_s was reduced to < −2·5 MPa. Reproduction was much more sensitive to reduced Ψ_s than was mycelial growth, and perithecia were produced only at Ψ_s ≥ −0·7 or −0·8 MPa on PDA amended with KCl or NaCl, respectively. Three isolates produced perithecia on PDA amended with sucrose only at Ψ_s ≥ −0·6 MPa, but the fourth isolate produced perithecia at ≥ −1·9 MPa. Colonization of the xylem early in disease development may provide an essential source of water for subsequent reproduction in the root cortex during plant senescence. Postharvest cultivation to expose and desiccate roots may prevent reproduction even when temperatures lethal to hyphae are not attained.     

Crop residue destruction strategies that enhance rather than inhibit reproduction of Monosporascus cannonballus

Destruction of infected crop residue is a management strategy commonly recommended for the control of many plant diseases. Based upon knowledge of the biology of the root-infecting fungus Monosporascus cannonballus , this strategy is a likely candidate for use in the management of vine decline of melons caused by this pathogen. Specifically, ascospores, the primary survival structure and inoculum for root infection, are produced on infected melon roots primarily after crop termination. Thus, destruction of infected roots prior to reproduction would be a very practical method of preventing inoculum build-up in soil. Results from this study demonstrated that two plant residue destruction methods commonly used by growers at crop termination [i.e. foliar application of a herbicide (glyphosate) and mechanical destruction of vines] significantly enhanced, relative to untreated controls, the rapidity and extent of pathogen reproduction on infected roots left in field after harvest.     

Infection and colonization of melon roots by Monosporascus cannonballus in two cropping seasons in Arizona and California

Although canopy collapse of melons (one of the above-ground symptoms of vine decline caused by Monosporascus cannonballus ) occurred late in the growing season, the onset of root infection occurred much earlier. In three early winter-spring and two late winter-spring crops, the onset of root infection occurred 47–65 and 35–36 days after planting, respectively. In contrast, in four summer-autumn crops, the onset of root infection occurred within 9–17 days after planting. Vine decline occurred commonly in winter-spring crops, but did not occur in any of the summer-autumn crops. Following the onset of root infection, the percentage of plants infected increased at rates of 0·031–0·036 and 0·038–0·070 per unit per day for winter-spring and summer-autumn crops, respectively, based on the monomolecular disease progress model. Root lesions were first observed 14–42 days after the onset of infection in winter-spring crops, and 14–28 days after the onset of infection in summer-autumn crops. Pathogen reproduction occurred primarily at the end of each growing season.     

草莓食叶害虫褐痣拟栉叶蜂生物学特性初步观察

褐痣拟栉叶蜂Priophorus fulvostigmatus Wei&Li是吉林地区草莓上新发生的一种食叶性害虫。本文通过室内饲养和田间观察的方法,记述了该虫的形态特征、发育历期、繁殖力及其生活习性。结果表明：褐痣拟栉叶蜂在恒温25℃条件下卵、幼虫、预蛹+蛹和成虫的发育历期分别为(6.96±0.37),(11.63±1.11),(11.47±1.13)d和(5.55±1.45)d,平均世代历期为(35.65±1.71)d,与在变温19～31℃(日平均25℃)条件下的历期略有差异。雌虫繁殖力较强,可进行有性生殖和孤雌生殖,在恒温25℃下平均单雌产卵量为(71.44±13.13)粒,变温19～31℃下为(64.38±16.61)粒;幼虫有6个龄期,随着幼虫龄期的增长,体长、体宽与头壳宽度逐渐增加,一头幼虫整个幼虫期可取食草莓叶片6 400.15 mm~2。该虫在吉林地区一年发生3代,以老熟幼虫在1.5～3 cm深的土层中吐丝结茧越冬。本研究基本明确了褐痣拟栉叶蜂各龄期的形态特征,并观察了主要生物学特性,以期为该害虫的识别和综合防控提供理论基础。     

安徽省首次发现肾形肾状线虫危害瓜蒌

肾形肾状线虫Rotylenchulus reniformis Linford & Oliveira是作物根部半内寄生植物线虫, 被列为危害最严重的十大植物线虫之一。本文对安徽省新发生瓜蒌肾形线虫病的病原进行鉴定并对其生活史进行初步研究。利用形态学和分子生物学将病原线虫鉴定为肾形肾状线虫R.reniformis, 系统发育分析表明其属于A型。肾形肾状线虫在瓜蒌根部完成生活史需要24 d, 每条雌虫平均产卵64粒, 繁殖系数R=(11.12±0.62)。本文系首次报道肾形肾状线虫在安徽省发生危害, 瓜蒌为肾形肾状线虫的新寄主。本研究为进一步掌握肾形肾状线虫的分布区域及潜在寄主及综合防控提供了理论依据。     

巴拉那根结线虫的鉴定及生物学特性

巴拉那根结线虫(Meloidogyne paranaensis)是咖啡上最具有毁灭性的根结线虫之一,可造成咖啡减产高达50%,目前主要发生在巴西、危地马拉和墨西哥,我国没有分布。本文介绍了巴拉那根结线虫的形态鉴定特征和生物学特性等内容。