First report of the fungus Fomitiporia maxonii Murrill causing citrus wood rot in commercial orange and grapefruit groves in Cuba

Cuban citriculture has recently been affected by important pests and diseases including black citrus aphid Toxoptera citricida Kirkaldy, citrus leafminer Phyllocnistis citrella Stainton, Asiatic citrus psyllid Diaphorina citri Kuwayama, Citrus tristeza disease, and huanglongbing. This complex of ‘invasive species’ is thought to be contributing to the increasing decline of commercial citrus groves. During several surveys carried out in commercial citrus areas of several provinces in Cuba, symptoms of dieback, characterized by the presence of abundant dry branches and wood rot were detected on Criolla Valencia orange, Marsh grapefruit trees on sour orange, and Cleopatra mandarin rootstocks. Samples of branches and trunk wood were processed and a fungus was isolated from all samples. Morphological, physiological and molecular characterization demonstrated that the isolated agent is Fomitiporia maxonii Murrill. The incidence of affected trees was high in most surveyed groves, reaching 100% in old groves. Symptoms similar to the ones found in naturally infected trees were reproduced on trees inoculated with pure cultures of the fungus, and the fungus was recovered in culture from inoculated trees, thus fulfilling Koch's postulates. This is the first report of an association of F. maxonii with citrus wood rot in Cuba.     

长春花接种丛枝菌根真菌对柑橘黄龙病菌的抑制效果

通过筛选获得具有显著促生和抗病能力的AM真菌菌株,为防治柑橘黄龙病提供理论依据和基础,并探索防治新途径。采用盆栽法,于长春花幼苗期分别接种17株AM真菌进行长春花农艺性状和对柑橘黄龙病的抗病性比较试验,研究不同丛枝菌根真菌菌株对长春花的促生效果及对柑橘黄龙病的抑制效果。结果表明,长春花接种AM真菌后,菌株GZ10、GZ5和JX70能显著促进植株生长,其中接种GZ10的株高和茎径分别比CK增加了23.1%和12.1%,接种GZ5的叶片数比CK增加了12.9%;接种菌株GZ1、BNMJ和PWJ有效提高了长春花对柑橘黄龙病的抗病和耐病能力,其相对防效分别为78.39%、66.87%和69.75%。     

杜鹃红山茶芽苗砧嫁接亲和性生理研究

杜鹃红山茶（Camellia azalea）为山茶科山茶属常绿灌木或小乔木,是中国特有珍稀濒危物种,在园林与观赏园艺方面具有广阔的应用前景,兼具有极高的科研价值。国内外关于杜鹃红山茶嫁接繁殖的研究主要集中在木质化砧木嫁接方面,而芽苗砧嫁接技术及芽苗砧嫁接亲和性生理的研究鲜有报道。为了从生理层面揭示杜鹃红山茶接穗与不同油茶芽苗砧的亲和性差异,本研究以广西栽培面积广泛的高州油茶、广宁红花油茶、岑溪软枝油茶、普通油茶为芽苗砧,以杜鹃红山茶当年生半木质化枝条为接穗进行芽苗砧嫁接,于嫁接后90 d,考察不同芽苗砧处理对杜鹃红山茶接穗死亡率、嫁接苗叶片中初生代谢产物含量、抗氧化生理指标以及光合色素含量的影响。结果表明：（1）不同芽苗砧木对杜鹃红山茶接穗的死亡率有显著影响,采用高州油茶作为芽苗砧,杜鹃红山茶嫁接死亡率最低,为18.5%;（2）不同芽苗砧木对杜鹃红山茶接穗叶片中可溶性蛋白含量及淀粉含量有显著影响,采用高州油茶砧木,嫁接苗叶片中可溶性糖、可溶性蛋白及淀粉含量均处于最高水平;（3）不同芽苗砧木对杜鹃红山茶嫁接苗叶片中脯氨酸含量及过氧化物酶（POD）活性有显著影响,采用高州油茶作为芽苗砧,嫁接苗叶片中脯氨酸和丙二醛（MDA）含量最低,超氧化物歧化酶（SOD）和POD活性最高;（4）不同芽苗砧木对杜鹃红山茶嫁接苗叶片中总叶绿素、叶绿素a及叶绿素b含量有显著影响,采用高州油茶作为芽苗砧的杜鹃红山茶嫁接苗叶片中总叶绿素、叶绿素a及叶绿素b含量均最高。研究认为,杜鹃红山茶接穗与高州油茶芽苗砧具有较好的亲和性,其嫁接苗抗性优于其他芽苗砧处理,叶片生长状况较好,具有较强的光合能力。     

2015—2017年广西桂林柑桔黑刺粉虱种群动态

本研究以广西桂林柑桔园黑刺粉虱（Aleurocanthus spiniferus）为对象,采用田间调查该粉虱卵、若虫、蛹和成虫的方法,研究了该粉虱的种群消长规律。结果表明：广西桂林柑桔园每年3月中旬—12月上旬的气温可满足黑刺粉虱的生长发育需要,2015—2017年间黑刺粉虱种群变动较大,黑刺粉虱卵至蛹全年发生高峰在5月中旬—7月上旬,其次在8月下旬—9月上旬;而成虫全年发生高峰在5月上旬,其次则在9月上中旬。本研究表明每年5—9月是桂林柑桔园黑刺粉虱自然种群增长较快的时期,生产上应用密切关注这一时期的该粉虱种群动态,并根据其危害情况及时采取必要的防治措施。     

广陈皮原料茶枝柑与其他典型柑橘成分差异分析

本文以广陈皮原料茶枝柑为对照,探究了其他典型的柑橘原料在可溶性糖、可溶性蛋白质、总黄酮、总多酚等方面的差异,分析其他橘皮作为茶枝柑替代品的可行性。结果表明,温州蜜柑、脐橙、湖北柑果皮的可溶性糖、可溶性蛋白质、总黄酮、总多酚含量与茶枝柑果皮相比均差异显著;采用GC-MS法检测出茶枝柑果皮精油的成分主要是D-柠檬烯、萜品烯、γ-松油醇、2-甲氨基-苯甲酸甲酯等,3种典型柑橘皮原料中的精油特征成分及D-柠檬烯含量与茶枝柑最为接近的均为脐橙。综合以上分析可知,脐橙作为广陈皮原料的替代品是最具前景的。     

Impacts of weather,shade cover and elevation on coffee leafminer Leucoptera coffeella (Lepidoptera: Lyonetiidae) population dynamics and natural enemies

We assessed the influences of ambient temperature, rainfall, shade cover and elevation on seasonal abundance of coffee leafminer Leucoptera coffeella (Guérin-Ménèville) and its natural enemies in coffee farms in the Soconusco region of Chiapas, Mexico. Mined coffee leaves were most abundant during the rainy season (i.e. historical average rainfall >200 mm/mo, April–November) compared to the dry season (<100 mm/mo, December–March), and at low (<600 m asl) relative to high (>900 m asl) elevations. The abundance of mined leaves increased with rainfall, and decreased with maximum daily temperatures. Coffee leafminer survivorship was highest during the dry season (>40%), when predation was lowest (<10%). Predation was the main source of coffee leafminer mortality, and was greatest during the rainy season (>25%) when coffee leafminer incidence was highest (>30% mined leaves per plant). None of the weather variables that were evaluated (viz. maximum and minimum temperatures, and rainfall) significantly impacted parasitism ratios. Shade cover moderated on-farm temperatures, by reducing maximum daily temperatures and any potential, direct impacts of rainfall on coffee leafminer, by providing partial shelter from rainfall, but did not significantly affect coffee leafminer incidence. In 48 h laboratory trials, coffee leafminer oviposition was highest at 28 °C (∼15 eggs/female), minimal at 25 °C (∼3 eggs) and nil at 20 °C, and higher during night-time hours (>8 eggs/female/day) compared to day-time hours (<1 egg). Historical average temperatures were higher at low elevation (yearly average ca. 25 °C; range = 18.0–32.0 °C) than at high elevation (ca. 21 °C; 13.5–28.5 °C), and we predicted that physical environmental conditions (i.e. night-time hours with temperatures > 20 °C) were permissive of coffee leafminer oviposition during twice as many hours each year at low elevation (4060 h) compared to high elevation (2081 h). Overall, our results suggested that evident differences in the abundance of coffee leafminer between elevations may be due in considerable part to differences in ambient temperatures, particularly night-time temperatures, rather than rainfall, shade cover, or elevation per se.     

Efficacy of biocontrol agents in planting mixes to colonize plant roots and control root diseases of vegetables and citrus

Tomato, bell pepper, celery and citrus were propagated in planting mixes amended with formulations of commercial biocontrol agents. Root colonization by selected biocontrol agents was evaluated for pepper, tomato and citrus, and found to be generally between 76 to 100% in both greenhouse ebb and flow, and bench-produced plants. Only colonization by Glomus intraradices was low, about 8%. All biological control agents, Trichoderma harzianum, Bacillus subtilis, G. intraradices, Gliocladium virens, and Streptomyces griseovirdis reduced crown rot of tomato in the field, with T. harzianum and B. subtilis being the most effective uniformly among four tests. Four biocontrols reduced Phytophthora root rot on citrus in the field, two applied as a drench to soil in pots reduced Thielaviopsis root rot on citrus, and two biocontrol agents in combination reduced celery root rot caused by Pythium and Fusarium spp., however, none improved above-ground plant growth or health of citrus and celery. Pepper crown and root rot caused by P. capsici was reduced by B. subtilis in one of two tests.     

Pest intensity-crop loss relationships for the leafminer fly Liriomyza huidobrensis (Blanchard) in different potato (Solanum tuberosum L.) varieties

Quantifying the relationship between plant injury and yield loss is a critical component for decision making in integrated pest management (IPM). The effects of foliar injury during different growth stages of potato (Solanum tuberosum L.), caused by natural populations of the leafminer fly Liriomyza huidobrensis (Blanchard) on potato yield, and the economic injury level for potato varieties with different maturity times were studied in the Cañete valley on the central coast of Peru. Field experiments were carried out during the potato cropping season (July–November) in the years 2005, 2007 and 2008 using early, middle-late and late potato varieties. Insecticides with different control efficiencies or the use of varying numbers of insecticide applications obtained various levels of leafminer fly infestation intensities. Leafminer fly infestation caused foliar injury in all potato varieties resulting in yield losses, which varied, according to the seasonal adult flight activity in each year of evaluation, between 22% in 2007 (2508 adults/trap/season) and 51% in 2005 (3147 adults/trap/season). Foliar injury increased with the development and growth of the potato plant, with the highest injury registered at the end of the cropping period. Early varieties showed higher foliar injury and yield loss than late potato varieties with the exception of Maria Tambeña, which is considered partially resistant to leafminer fly infestation. Yield losses increased linearly by each percentage of foliar injury in all potato varieties. Critical point and multiple point models made it possible to identify the potato growth stage at which leafminer infestation had the greatest effect on yield. Pest infestation-crop loss relationships indicated that the accumulated foliar injury up to the growth stages of flowering and berry formation produced the highest yield losses in the different potato varieties. Economic injury levels varied according to control costs and commodity values in each potato variety (Desiree: 21–28%, Revolucion: 34–47%, Canchan: 31–40%, Maria Tambeña: 40–53%, Tomasa: 55–74%, and Yungay: 40–54% of foliar injury). Potato varieties can tolerate considerable levels of foliar injury by the leafminer fly before control measures are needed. The use of the economic injury levels is suggested as a decision support tool for managing the leafminer fly at reduced pest management costs.     

广西柑橘碎叶病和叶斑病调查及其病原的遗传多样性分析

调查了广西南宁、崇左、柳州、桂林、玉林、河池、贺州及防城港等主要柑橘种植区的柑橘碎叶病和叶斑病的发生情况,并对其病原柑橘碎叶病毒（Citrus tatter leaf virus, CTLV）、苹果茎沟病毒（Apple stem grooving virus, ASGV）和柑橘叶斑病毒（Citrus leaf blotch virus, CLBV）进行了RT-PCR检测、病毒序列测定和遗传多样性分析。结果发现,在所有疑似柑橘病毒病样品中,CTLV检出率为7.3%,CLBV检出率为5.5%,ASGV检出率为3.0%。其中在南宁、桂林和玉林3个主要柑橘种植区采集的疑似柑橘病毒病样品的3种病毒病检出率合计分别为21.2%、28.6%和7.6%,且存在多种病毒复合侵染的现象。将克隆到的上述3个病毒分离物的病毒片段,分别与已报道的相应病毒的代表性分离物的病毒片段进行系统进化分析,结果表明,ASGV和CTLV的中国分离物在进化关系上均呈寄主相关性,ASGV的日本分离物则与地理位置相关性更强,而韩国和印度的分离物未表现出明显的寄主相关性和地理位置相关性。柑橘和苹果的ASGV和CTLV分离物均表现与地理位置相关,而梨的ASGV和CTLV分离物却与地理位置和寄主均不相关;CLBV分离物则呈明显的寄主相关性。本研究首次报道了广西柑橘碎叶病和柑橘叶斑病的发生情况及其病原的遗传多样性与系统进化关系,为柑橘病毒病的诊断和防治提供参考依据。     

酸橘砧和枳砧沙糖橘果园土壤、叶片、果实养分比较与相关性分析

为了解广东省清远市沙糖橘园土壤养分丰缺状况,分析结果树不同砧穗组合叶片、果实养分丰缺状况,为沙糖橘营养科学管理、果园合理施肥及产业提质增效提供科学依据。采集清远市27个10~15年生枳砧和酸橘砧沙糖橘果园的土壤、叶片及果实,分析土壤、叶片及果实矿质养分含量,分析土壤、叶片及果实养分含量间的相关性。结果表明,清远沙糖橘果园土壤pH整体偏酸性,土壤有机质较丰富,有机质含量适量及以上果园占比70.4%。速效N含量缺乏果园为51.8%,81.5%的果园土壤速效P超量,有效K超量的占比48.1%,多数果园土壤有效Mn、有效Zn、有效Mo含量较适宜,但有效Ca、有效Mg、有效B缺乏占比分别达到81.5%、88.9%、77.8%。枳砧、酸橘砧沙糖橘叶片矿质养分丰缺程度存在差异,枳砧沙糖橘叶片N、B、Ca含量较少缺乏,而酸橘砧沙糖橘叶片3种元素含量存在严重缺乏的现象,2种砧木沙糖橘叶片中Cu、Mg均相对缺乏,Mo含量均严重缺乏。枳砧和酸橘砧沙糖橘果实矿质养分的大量元素中N、K含量高于P,中量元素Mg含量低于Ca含量,微量元素中Fe含量最高。枳砧沙糖橘果实单果重、果形指数、可食率、可滴定酸、可溶性固形物、Vc含量等指标均低于酸橘砧。2种砧木的沙糖橘果园土壤矿质养分与叶片矿质养分间,枳砧Mg、Fe分别呈极显著、显著正相关,酸橘砧B、Fe均呈显著负相关,枳砧沙糖橘叶片与果实中Mo含量显著正相关,酸橘砧沙糖橘叶片、果实、土壤三者间Mo含量均为极显著正相关。清远市沙糖橘果园管理应注重改良土壤酸碱度,施用适当配比的N、P、K肥,深施有机肥的同时适量添加或叶面喷施Zn、Mg、B、Ca、Mo,合理控制含Mn农药的使用次数。     

Resistance to insects by cabbage lines developed in New York when grown in South Texas

Brassica oleracea (L.) germplasm, developed at the New York Agricultural Experiment Station (NYAES), Geneva, as advanced cabbage breeding lines with resistance to lepidopterous pests, was grown in south Texas. Resistance, as measured in terms of insects present on plants, of the breeding lines to arthropod pests was compared with that of cultivars commonly grown in south Texas by monitoring populations of insect pests on the various lines and cultivars. Breeding lines developed at NYAES retained their desired characteristics for resistance to naturally occurring populations of Trichoplusia ni (Hübner) and Plutella xylostella (L.) and also were found to be resistant to Brevicoryne brassicae (L.). A red cabbage cultivar, Red Rock, was found to be more susceptible to Pemphigus populitransversus Riley populations than all other lines or cultivars. Murgantia histrionica (Hahn) was present during one growing season and some NYAES lines that were infested with low numbers of lepidopterous larvae and aphids became heavily infested with this species. Spodoptera exigua (Hübner) populations did not occur in great enough abundance to evaluate differences in resistance among lines and cultivars in 1984 or 1985.     

Potential use of selected citrus rootstocks and interstocks against HLB disease in Malaysia

Huanglongbing (HLB), also known as citrus greening disease, has spread to and is seriously threatening the citrus industry in more than 40 countries. The HLB pathogen is a phloem limited bacteria, Candidatus Liberibacter spp. There is little information pertaining to the effects of different citrus rootstocks and interstocks against HLB in Citrus reticulata. The objective of this study was to evaluate the beneficial effects of different combinations of citrus rootstocks and interstocks against HLB using side grafting. There were no symptoms of HLB when C. grandis was used as rootstock with C. hystrix as the interstock and vice versa six months after inoculation. However, C. Liberbribacter asiaticus was detected in the scion using second PCR amplification. A high rate of disease severity was observed when C. aurantum was used as rootstock and C. aurantifolia as the interstock and vice versa. This study showed that C. Liberibacter asiaticus can be detected by conventional PCR and characteristics of their detrimental effects include low rate of vegetative growth and reduction of dry matter, root dry matter, plant height and stem diameter.     

苦瓜嫁接砧木对象耳豆根结线虫的抗性鉴定

根结线虫是危害农业生产的重要的土传病害之一,其中象耳豆根结线虫在近几年发展成为华南地区的优势种群,防治较为困难,严重影响了苦瓜的产量和品质,生产中较多采用嫁接砧木的防治措施.为筛选抗象耳豆根结线虫的苦瓜砧木品种,以18份苦瓜砧木品种为试验材料,采用盆栽幼苗人工接种象耳豆根结线虫的方法,接种45 d后,测量供试材料的相对...     

17种报春苣苔属植物的组培苗移栽季节研究

探讨不同季节对报春苣苔属植物组培苗移栽成活的影响,为其今后组培苗工厂化、规模化生产提供技术支持。以17种报春苣台属植物的组培生根苗为材料,研究季节对移栽成活的影响,分析不同物种间在同一季节的移栽成活差异以及同一物种在4个不同季节的移栽成活差异。大部分种类在春季移栽具有较高的成活率;成活率最高与最低的种类为三苞报春苣苔和粗茎报春苣苔,成活率分别为100.0%、51.3%;适宜春季移栽的种类是：贵港报春苣苔、硬叶报春苣苔、永福报春苣苔、紫花报春苣苔、三苞报春苣苔、阳朔小花苣苔、褐纹报春苣苔、柳江报春苣苔、尖萼报春苣苔、大根报春苣苔。17个种类在夏季移栽具有较低的成活率;成活率最高与最低的种类为大根报春苣苔和漓江报春苣苔,成活率分别为68.7%、15.3%。在17个种类中,超过一半的种类在秋季、冬季移栽具有较高的成活率。秋季移栽成活率最高为桂海报春苣苔、那坡报春苣苔,均为100.0%,成活率最低为褐纹报春苣苔,为20.0%;适宜秋季移栽的种类是：桂海报春苣苔、粗茎报春苣苔、那坡报春苣苔。冬季移栽以冬花报春苣苔的成活率最高,为100.0%,永福报春苣苔的成活率最低,为32.7%;适宜冬季移栽的种类是：桂中报春苣苔、紫萼报春苣苔、冬花报春苣苔、漓江报春苣苔。17个种类的移栽季节以春季的最好,夏季最差,秋季和冬季介于春季和夏季之间。不同季节不同种类移栽成活率不同,不同种类其适宜移栽的季节不同,应根据季节移栽合适的种类以保证其获得较高的成活率。     

大豆远缘嫁接诱变技术的优化

为完善和优化大豆远缘嫁接诱变技术体系,以与大豆远缘的8种植物为砧木,以4个大豆品种(系)为接穗进行嫁接试验。结果表明:以6～8日龄的大豆幼苗作为接穗可提高远缘嫁接成活率,其中7日龄大豆幼苗的嫁接成活率最高。砧木类型对远缘嫁接大豆后代诱变率和诱变方向有重要影响,番茄/龙选1号、蓖麻/科绿2号、生姜/科绿2号、蓖麻/田丰90和洋姜/田丰90嫁接组合的诱变率最高,同时以生姜和番茄作为砧木与大豆接穗嫁接后代可出现高蛋白、高油和晚熟类型突变;以甘薯和马铃薯为砧木与大豆接穗嫁接后代可出现多分枝和丰产类型突变;以蓖麻和洋姜为砧木与大豆接穗嫁接后代可出现抗逆性强(抗倒伏)和植株矮化的突变类型;以南瓜和葫芦为砧木与大豆接穗嫁接后代可出现晚熟和高大植株的突变类型。嫁接亲和力评价结果表明,以南瓜、马铃薯、番茄和生姜作为砧木的嫁接亲和力较高,以科绿2号为接穗的嫁接亲和力较高。     

Field study of the interaction between Orobanche crenata Forsk. and some new lines of Vicia faba L. in Egypt

In Egypt, some newly derived lines of faba bean (Vicia faba L.) as well as Giza 402, all of which had shown a certain resistance against the parasitic weed Orobanche crenata Forsk., were tested in the field. For reasons of comparison, the susceptible cultivars Giza 3 and Reina Blanca were included in this test. Faba bean plants and Orobanche attachments were regularly harvested and examined. The susceptible cultivars completely collapsed before the end of the growing season, whereas others, particularly line 402/294, remained alive until pod formation was completed. It appeared that fewer Orobanche spikes emerged on the new lines and Giza 402. Evidence is given that this was not due to avoidance mechanisms, such as smaller root mass, a deeper root system or lack of germination stimulants. Numbers of Orobanche attachments per unit of lateral root length were found to be low. Hence, it could be concluded that these lines are partially resistant; this resistance must be due to some defence mechanism in their roots. The few Orobanche plants attached grew very fast so that final Orobanche dry weight was similar in resistant and susceptible host plants. Further experiments, including broomrape-free controls, are required to study whether some tolerance mechanism might be involved.     

粳稻种质资源稻瘟病抗性及抗性基因分析

为提高冀东稻区水稻抗稻瘟病育种水平,对157份粳稻资源通过田间诱发感病鉴定其稻瘟病抗性,并利用12个抗病基因标记进行基因型鉴定.结果表明,157份粳稻资源中表现为抗、中抗、中感、感及高感材料分别为2、70、64、9、12个,其中,材料ZY1和ZY2表现为抗.Piz和Pid3这两个抗病基因出现频率最高,而Pigm、Pia...     

不同西瓜嫁接砧木的筛选与研究

以西瓜品种‘早佳84-24’为对照和接穗,分别与6个不同类型的砧木进行嫁接,探讨不同砧木对西瓜生理性状、果实品质和抗病性等的影响,从中筛选出适合‘早佳84-24’嫁接砧木的优良品种。试验结果表明,在6个砧木品种中,‘刚强’‘Nf1’与西瓜品种‘早佳84-24’嫁接后,长势旺盛、产量高、抗病性强,可作为三亚地区西瓜嫁接栽培的砧木品种。     

14种AM真菌对枳生长的影响

在盆栽条件下,以柑橘砧木枳（Fructus aurantii）幼苗为试验材料,在基质中接种从广西土壤中分离得到的不同丛枝菌根（AM）真菌菌株,探讨不同AM真菌对枳根系的侵染能力和植株生长的影响。结果表明：用于试验的14个AM真菌菌株均能与枳根系形成共生关系,平均侵染率为36.16%,其中侵染率最高的菌株是黄雷德克囊霉（Redeckera fulvum, Rf）,侵染率高达92.83%,侵染率最低的菌株是副冠球囊霉（Glomus coronatum, Gc）,侵染率仅为0.23%;接种黄雷德克囊霉、摩西斗管囊霉（Funneliformis mosseae, Fm2）和副冠球囊霉这3个菌株处理的枳植株的株高、茎粗、叶片数和叶柄长均高于CK,是枳的优势菌株,能促进枳的生长。     

Efficacy of insecticides against major insect pests of potatoes in hot climates of Peru

Soil-incorporated and foliar-applied insecticides, alone and in combination, were tested in two different tropical sites of Peru. At San Ramon (altitude 800 m) major pests during the wet season were Diabrotica spp. and Myzus persicae. Soil-incorporated insecticides gave protection against Diabrotica but not M. persicae, and yields were significantly lower with these compared with the foliar-applied insecticide, carbofuran. Mean yield was inversely and significantly correlated with mean number of Diabrotica individuals per plant (r=0·989; 0·01 <P<0·05). The foliar-applied insecticide, season, major pests were Phthorimaea operculella, M. persicae and Feltia spp. Mean yield was inversely correlated with mean number of larval mines by P. operculella on foliage (r=0·976;0·02 <P<0·05). The foliar-applied insecticide methomyl, reduced pest damage and increased yields significantly. The major pests during the dry season at Yurimagus (altitude 180m) were Diabrotica spp. Foliar application of carbaryl alone, or in combination with soil-incorporated insecticides, was equally effective in reducing damage and yield loss. An inverse significant correlation (r=0·985; 0·01<P<0·02) for yield vs. damage from Diabrotica spp. was observed.