薇甘菊粗提物在椰心叶甲上的防控潜力

为了评价外来入侵杂草薇甘菊Mikania micrantha在害虫综合防治方面的潜力,为椰心叶甲Brontispa longissima的防控提供参考,测定了薇甘菊提取物对椰心叶甲室内生物活性和田间防治效果。结果表明：不同极性溶剂对薇甘菊活性物质提取率中,以甲醇和乙醇的提取率最高（甲醇、乙酸乙酯、正己烷、石油醚、三氯甲烷、蒸馏水、乙醇的提取率分别为10.54%,7.17%,6.22%,6.28%,8.67%,8.62%和10.36%）;薇甘菊甲醇和乙醇提取物均对椰心叶甲表现出一定的生物活性,且乙醇提取物对各龄幼虫及成虫的活性均高于甲醇提取物,其中乙醇提取物对椰心叶甲1～5龄幼虫和成虫LC₅₀分别为7.09,7.88,8.93,11.88,13.26和17.46 mg/g,而甲醇提取物相应LC₅₀值分别为12.36,14.85,15.89,17.46,19.91和27.81 mg/g;两种提取物均能造成椰心叶甲蛹的羽化延迟、成虫畸形、卵孵化时间延迟等情况。大田试验结果表明,薇甘菊乙醇提取物对椰心叶甲表现出显著的防治效果,其中100和20 mg/mL处理组在处理后的第7天其虫口减退率均达到80%以上。结论：薇甘菊提取物对椰心叶甲具有一定的生物活性和防控潜力。     

海南椰心叶甲病原菌金龟子绿僵菌的分离、鉴定及其生防潜力

椰心叶甲[Brontispa longissima（Gestro）]是椰子的重要害虫,近年来,该虫在海南岛发生普遍,椰子受害严重。由于椰心叶甲受到自然界中某些致病微生物的侵袭,在受害的椰子树心叶上常可发现椰心叶甲僵虫,并发现大部分僵虫表面长出了霉菌,本研究的目的在于从椰心叶甲僵虫表面的霉菌中分离出绿僵菌,并对分离菌株进行鉴定和致病性测定。从僵虫表面刮下孢子或菌丝体,置于绿僵菌选择性培养基（DOA）上培养,挑出真菌菌落,经纯化后,进行生物学特性、菌落生长速率及产孢量的测定,并从PPDA、OMA、VSA和PDA中筛选菌落生长及产孢最适培养基,同时对所分离的菌株进行对椰心叶甲的致病性测定。结果表明,所有分离菌株均鉴定为金龟子绿僵菌[Metarhizium anisopliae（Metschnikoff）],PPDA是菌落生长及产孢的最适培养基,大多数菌株对椰心叶甲有较强的致病力。选取强毒菌株MA4在田间进行防治效果的初步测定,结果表明,该菌株能显著降低椰心叶甲成虫的虫口密度。这些金龟子绿僵菌菌株是首次从海南的椰心叶甲僵虫中分离到的昆虫病原真菌,该菌对海南的椰心叶甲具有很好的生防潜能。     

绿僵菌侵染对椰心叶甲酚氧化酶活性的影响

对椰心叶甲Brontispa longissima(Gestro)成虫血淋巴中酚氧化酶的特性进行分析,并研究绿僵菌(Metarhizium anisopliae)侵染对血浆甲酚氧化酶活性的影响。结果显示,椰心叶甲成虫的血浆及血细胞裂解液中均检测到酚氧化酶活性,且昆布多糖及胰蛋白酶可显著提高其活性。绿僵菌MA-4侵染组在侵染后第1至第5d的血浆酚氧化酶活性高于未侵染组(P<0.05),但是椰心叶甲成虫体内注射10μg昆布多糖后,侵染组的酚氧化酶活性显著低于未侵染组(P<0.05),表明绿僵菌一方面对可激活椰心叶甲的酚氧化酶原激活系统,另一方面又可抑制昆布多糖对椰心叶甲酚氧化酶原激活系统的诱导作用。     

昆明地区鲜切花产区朱砂叶螨抗药性监测

采用玻片浸渍法测定了昆明地区花卉朱砂叶螨Tetranychus cinnabarinus(Boisduval)对阿维菌素、甲氨基阿维菌素苯甲酸盐、溴虫腈、丁醚脲、炔螨特和哒螨灵的抗性。结果表明,昆明北郊和呈贡地区玫瑰上的朱砂叶螨雌成螨对阿维菌素与甲氨基阿维菌素苯甲酸盐产生了极高的抗药性,阿维菌素对2个地区的朱砂叶螨的LC50分别为40.25mg·L-1和19.67mg·L-1,相对毒力指数分别为敏感品系的2441.08倍和1192.86倍;甲氨基阿维菌素苯甲酸盐对其LC50分别为118.18mg·L-1和9.24mg·L-1,相对毒力指数是敏感品系的2805.73倍和219.35倍。昆明北郊的朱砂叶螨对溴虫腈的相对毒力指数是敏感品系的2371.40倍,呈贡和晋宁分别为162.01倍和173.38倍。丁醚脲对北郊、呈贡和晋宁朱砂叶螨的LC50分别为244.58mg·L-1、385.41mg·L-1和54.93mg·L-1,相对毒力指数在3.01倍～21.10倍之间。北郊、呈贡和晋宁的朱砂叶螨种群对炔螨特和哒螨灵的LC50分别为155.39mg·L-1、424.49mg·L-1和62.70mg·L-1,其相对毒力指数是敏感品系的6.45倍、17.63倍和2.60倍。朱砂叶螨对药剂抗药性水平趋势从高到低为:阿维菌素、甲氨基阿维菌素苯甲酸盐>溴虫腈、丁醚脲>炔螨特、哒螨灵,抗性最高的地区为昆明北郊,晋宁相对较低。     

水椰八角铁甲和椰心叶甲对椰子和银海枣的寄主选择性

【目的】水椰八角铁甲和椰心叶甲均为棕榈科植物的重要入侵害虫,两者的外部形态、取食部位和危害特征相似。研究它们的寄主选择性有助于了解这2种害虫的扩散和成灾机制。【方法】在室内用椰子和银海枣2种寄主植物分别饲养水椰八角铁甲和椰心叶甲,研究在不同寄主植物上水椰八角铁甲和椰心叶甲的存活率、产卵率、发育历期等以及这2种害虫对不同寄主植物的选择性。【结果】水椰八角铁甲在2种寄主上的存活率差异显著,除了卵期和蛹期之外,幼虫期各虫态在银海枣上的存活率明显比在椰子上的存活率高;椰心叶甲在椰子上的存活率高于银海枣,各虫态平均存活率分别为95%和86%。取食银海枣的水椰八角铁甲达标准卵量概率为0.23,取食椰子不产卵,无法完成整个世代;取食椰子的椰心叶甲达标准卵量概率为0.86,取食银海枣不产卵,也无法完成整个世代;水椰八角铁甲取食银海枣完成世代的实验种群趋势指数为12.55,椰心叶甲取食椰子完成世代的实验种群趋势指数为66.55。【结论】水椰八角铁甲和椰心叶甲分别对银海枣和椰子这2种寄主植物具有明显的选择性。在海南椰子树的数量远远超过银海枣,该实验结果在一定程度上解释了椰心叶甲在海南岛广泛分布而水椰八角铁甲只是零星发生的原因。     

6种杀虫剂对南美番茄潜叶蛾的毒力及田间防效

[目的]研究6种杀虫剂对南美番茄潜叶蛾卵、幼虫和成虫的毒力及其在温室番茄上的防治效果,为南美番茄潜叶蛾防治提供高效杀虫剂和施药技术。[方法]采用浸渍法和药膜法测定了6种杀虫剂对南美番茄潜叶蛾卵、幼虫和成虫的毒力,田间调查毒力较高杀虫剂对温室番茄上南美番茄潜叶蛾防效。[结果] 6种杀虫剂中的乙基多杀菌素、甲氨基阿维菌素苯甲酸盐和阿维菌素对南美番茄潜叶蛾卵有毒力作用,致死中浓度（LC₅₀）分别为1.415、13.588和23.194 mg·L^-1。6种杀虫剂对南美番茄潜叶蛾幼虫的LC₅₀分别为：阿维菌素0.026 mg·L^-1、四唑虫酰胺0.052 mg·L^-1、甲氨基阿维菌素苯甲酸盐0.057 mg·L^-1、乙基多杀菌素0.072 mg·L^-1、氯虫苯甲酰胺0.484 mg·L^-1和呋虫胺2.039 mg·L^-1。对于南美番茄潜叶蛾成虫,24 h时,仅甲氨基阿维菌素苯甲酸盐和四唑虫酰胺对成虫有较高毒力;72 h时,6种杀虫剂对成虫的LC₅₀分别为：甲氨基阿维菌素苯甲酸盐0.390 mg·L^-1、乙基多杀菌素1.646 mg·L^-1、四唑虫酰胺2.630 mg·L^-1、呋虫胺5.577 mg·L^-1、阿维菌素22.502 mg·L^-1和氯虫苯甲酰胺39.636 mg·L^-1。在成虫盛发期第4天施药,阿维菌素、四唑虫酰胺、甲氨基阿维菌素苯甲酸盐、乙基多杀菌素在南美番茄潜叶蛾危害严重的温室番茄上防效达80%以上。[结论]阿维菌素、四唑虫酰胺、甲氨基阿维菌素苯甲酸盐、乙基多杀菌素、氯虫苯甲酰胺和呋虫胺对南美番茄潜叶蛾卵、幼虫或成虫有较高毒力,其中阿维菌素、四唑虫酰胺、甲氨基阿维菌素苯甲酸盐和乙基多杀菌素田间防效较好。     

不同杀虫剂对锡兰玻壳蚧的室内毒力及田间防效

【目的】锡兰玻壳蚧是我国余甘子上新发现的重要害虫,对农业生产及生态安全构成严重威胁。本研究旨在筛选出高效理想的防治药剂,为生产中科学用药提供依据。【方法】采用浸渍法测定8种杀虫剂对锡兰玻壳蚧的室内毒力,采用喷雾法评价5种毒力较好药剂的田间防效。【结果】室内毒力测定结果表明:毒死蜱、啶虫脒、吡虫啉、阿维菌素、甲维盐对1、2龄若虫的毒力较强,48 h致死中浓度(LC₅₀)分别为11.1245、26.2376 mg·L^-1,17.5381、26.1910 mg·L^-1,27.5896、34.2868 mg·L^-1,26.5876、38.8034 mg·L^-1,29.0528、43.0443 mg·L^-1;毒死蜱和阿维菌素对3龄若虫、雌成虫的毒力较强,48 hLC₅₀分别为87.3427、495.8339 mg·L^-1,95.4751、1131.6430 mg·L^-1;螺虫乙酯、吡丙醚和高效氯氟氰菊酯对各虫期的毒力均较弱;吡虫啉、阿维菌素、啶虫脒、甲维盐对各龄若虫的毒力比差异较小,毒死蜱的毒力比差异较大,但后者对各龄若虫的毒力均较强。田间防效结果表明:毒死蜱和阿维菌素对田间种群增长抑制效果最好,药后7 d防效分别为96.90%、92.00%;吡虫啉、甲维盐和啶虫脒对低龄若虫种群速杀效果较好,药后7 d防效分别为78.06%、67.62%、62.78%。【结论】锡兰玻壳蚧的化学防治应于1~2龄若虫期进行,推荐阿维菌素、毒死蜱、吡虫啉、甲维盐和啶虫脒轮换使用;3龄雌若虫及雌成虫盛发期推荐使用毒死蜱和阿维菌素防治。     

椰心叶甲啮小蜂的繁殖生物学研究

对椰心叶甲啮小蜂羽化、求偶、交配、产卵、繁殖现象进行了观察研究。结果表明,补充营养对雌蜂的寿命和繁殖力均有影响。没有补充营养的情况下,雌蜂的平均寿命为2.48 d,一生可产21.43粒卵;每天补充10%蜜糖水,且雌蜂与寄主(椰心叶甲初蛹)比例为1:3时,雌蜂平均寿命为13.43 d,一生可产53.6粒卵;每天补充10%蜜糖水,且雌蜂与寄主(椰心叶甲初蛹)比例为1:1时,雌蜂平均寿命为14.78 d,一生可产42.5粒卵。椰心叶甲啮小蜂对水椰八角铁甲蛹的寄生率为82.25%,平均每寄主出蜂量为12.24头。     

低温贮存对椰心叶甲啮小蜂品质的影响

研究低温贮存椰心叶甲蛹Brontispa longissima(Gestro)和椰心叶甲僵蛹对椰心叶甲啮小蜂Tetrastichus brontispae Ferriere种群品质的影响。寄生10℃低温贮存1~4日龄椰心叶甲蛹结果表明,1日龄椰心叶甲蛹的寄生率、羽化率、出蜂率、单蛹出蜂数、后代寄生能力均优于其他日龄,其次为2、3日龄的椰心叶甲蛹,最差为4日龄的椰心叶甲蛹。1日龄椰心叶甲蛹在10℃下贮存5,10,15,20d后,上述生物学指标和种群参数均随贮存天数增加而降低,其中以5d和10d的净生殖率、内禀增长率和周限增长率较未经低温贮存的差异小。1~11日龄椰心叶甲僵蛹于10℃贮存10d的结果表明,8日龄椰心叶甲僵蛹的雌蜂寿命、羽化率、单蛹出蜂数、寄生能力均优于其他日龄僵蛹。8日龄椰心叶甲僵蛹在10℃下贮存5,10,15,20d后,上述生物学指标和种群参数均随贮存天数增加而显著低于对照。     

杀虫剂对稻纵卷叶螟的室内毒力及田间药效

分别测定了8种杀虫剂对稻纵卷叶螟的室内毒力及田间防效,结果表明:8种杀虫剂对稻纵卷叶螟的LC50为0.671-10171.07mg.L-1,毒力由高到低的顺序为:甲氨基阿维菌素苯甲酸盐>阿维菌素(B1)>氟虫腈>氟铃脲>丙溴磷>毒死蜱>三唑磷>杀虫单。甲氨基阿维菌素苯甲酸盐、阿维菌素(B1)、氟虫腈、氟铃脲对稻纵卷叶螟的毒力分别为杀虫单的15180.7、5619.3、1611.9、997.2倍。在推荐剂量下,氟虫腈、丙溴磷、毒死蜱对稻纵卷叶螟防治效果较好,防效分别达86.11%、84.73%、83.37%。     

5种杀螨剂对不同螨态荔枝叶螨的毒力评价和田间防效

为了综合评价常用杀螨剂对荔枝叶螨Oligonychus litchii的室内毒力,在室内分别采用Potter喷雾法、浸叶碟法和浸叶法测定了5种常用杀螨剂对荔枝叶螨成螨、卵和若螨的毒力,并测定了5种杀螨剂对荔枝叶螨的田间防效。室内毒力结果表明:哒螨灵、阿维菌素对荔枝叶螨成螨和若螨有较高的毒力,联苯肼酯对成螨和若螨的毒力较低,而螺螨酯和乙螨唑对成螨基本无活性,对若螨有一定的毒力;5种杀螨剂对卵的毒力大小依次为乙螨唑螺螨酯哒螨灵阿维菌素联苯肼酯。田间防效试验中,15%哒螨灵乳油和1.8%阿维菌素乳油对荔枝叶螨的总体防效较好,药后1 d防效高于70%,药后10 d防效达100%,药后20 d防效仍在90%以上,速效性和持效性均较好;240 g/L螺螨酯悬浮剂和110 g/L乙螨唑悬浮剂对荔枝叶螨药后3 d防效均低于70%,而药后20 d的防效高于90%,说明两药剂速效性较差但持效性较好;43%联苯肼酯悬浮剂药后1、3 d防效低于阿维菌素和哒螨灵,高于螺螨酯和乙螨唑,药后15 d防效开始下降。在田间防治荔枝叶螨时,若荔枝叶螨发生早期、成螨较少时建议施用螺螨酯或乙螨唑,而荔枝叶螨种群中成螨、若螨较多时推荐施用阿维菌素、哒螨灵或联苯肼酯。     

棕榈科植物有害生物椰心叶甲的风险性分析

运用有害生物危险性分析(Pest Risk Analysis,PRA)的方法,从国内分布状况、潜在危害性、寄主植物经济重要性、传播扩散的可能性,以及危险性的管理难度等方面,综合评价了椰心叶甲的危险性。结果表明椰心叶甲对我国是具高度危险性的有害生物。     

Some studies on Nigerian palm wine with special reference to yeasts

The identification and enumeration of yeasts and the effect of chemical preservatives on the yeast load in Nigerian palm wine have been studied. Yeast found largely belong to the genus Saccharomyces. Other genera found were Candida, Endomycopsis, Hansenula, Kloeckera, Pichia, Saccharomycoides and Schizosaccharomyces. The viable yeast count ranged from 0.5 × 10⁷ cfu/ml to 4.2 × 10⁹ in both fresh Elaeis and Raphia spp. of palms. Yeasts in palm wine were least sensitive to sodium nitrate and most sensitive to sodium benzoate. The addition of these two chemical preservatives amongst others reduced the yeast count to 3.2 × 10⁸ (in Raphia sp.), and 4.1 × 10⁹ (in Elaeis sp.) with 0.025% sodium nitrate and 1.2 × 10⁶ (in Raphia sp.) and 1.9 × 10⁷ (in Elaeis sp.) with 0.1% sodium benzoate. The values of the yeast count in bottled and fresh palm wine were between 1.3 × 10³ cfu/ml to 9.8 × 10⁶ and 0.5 × 10⁷ to 4.2 × 10⁹, respectively. Maximum values of actual dry and theoretical yeast weights were 1.09 and 42 mg/ml, respectively.     

Functional response of Tetrastichus gallerucae (Hym: Eulophidae) to different densities of the elm leaf beetle eggs,Xanthogaleruca luteola (Col: Chrysomelidae)

The elm leaf beetle is often considered as much of an indoor nuisance as a garden pest since large numbers of adults migrate into homes seeking a protected place to overwinter. Outdoors, both adults and larvae feed on the emerging leaves of virtually all species of elm trees, leaving skeleton zed foliage in their wake. Repeated severe infestations can markedly weaken a host tree, making it susceptible to other insects and diseases. The elm leaf beetle does not transmit the well-known Dutch elm disease, which is carried by another insect than elm bark beetle. The functional response of Tetrastichus gallerucae bees, that is the most important natural enemy of egg elm beetle Xanthogallerucae luteola, has been detected in Kerman province. The experiment was carried out in the growth room under conditions of 25 ± 1°C, 60 ± 5 RH and 16L:8D. Every female bee was exposed for 24 hours at densities of 2, 4, 6, 8, 10, 12, 16, 20, 30 and 40 eggs of elm leaf beetle. Every density had 10 repetitions. The results showed that T. gallerucae has the second type of functional response. The searching efficiency and the handling time of T. gallerucae was 2.63 and 0.114 on the eggs of elm leaf beetle and 2.193 and 0.112 on the eggs of hostess with diluted honey.     

Study on some biological characteristics of Tetrastichus gallerucae (Hym. Eulophidae), important parasitoid of Elm leaf beetle eggs in Kerman,Iran

In this study, a number of biologic characteristics of Tetrastichus gallerucae, the most important natural enemy of Xanthogaleruca luteola (Col.: Chrysomellidae), were studied. Experiments were carried out in growth room with a temperature of 25°C±1°C, relative humidity of 60%±5% and light period of 16L:8D. The results demonstrated the following outcomes: without food and host egg, the longevity of male and female bees was respectively, 1.23 and 1.35 days. On the host egg, their longevities were 3.85 and 6.02 days, respectively. On rarefied honey their longevities were 14.04 and 24.74 days, respectively and on the host eggs together with rarefied honey, their longevities were 13.4 and 34.72 days, respectively. The average growth period times in the egg of elm leaf beetle of male and female bees were 12.97 and 12.63 days, respectively. The percentage of female bees decreases as the longevity of the insects increases. These bees lay eggs in the 1–9-day-old eggs of elm leaf beetle but 1-day-old eggs of the host are preferred by T. gallerucae.     

Avermectin类农药对美洲斑潜蝇的生物活性

Avermectin类农药对美洲斑潜蝇Liriomyzasattvae Blanchard生物活性的室内研究结果表明： 揭阳霉素对美洲斑潜蝇1、2、3龄幼虫的LC₅₀分别是1.54×10^-4 g/L、3.73×10^-4 g/L、1.99×10^-3g/L;害极灭对上述幼虫的LC₅₀分别是1.48×10^-4g/L、3.68x10^-4 g/L和1.97×10^-3 g/L。美洲斑潜蝇幼虫对Avermectln类农药以1龄最敏感,其中揭阳霉素对3龄幼虫的LC₅₀是1龄的12.9倍。揭阳霉素对雌成虫24 h、48 h的LC₅₀分别是3.12×10^-3 g/L和2.08×10^-3 g/L,其对美 洲斑潜蝇取食、产卵拒避持效期分别是4-8天和10天。使用浓度0.005 g/L揭阳霉素处理6天、8天和10天后接虫,幼虫的存活率分别是0、16.13%和28.07%。田间使用浓度0.005 g/L的揭 阳霉素和0.0045 g/L几的害极灭分别处理,6天后的校正虫口减退率分别为91.0%和90.9%,两者差异不显著,而使用浓度0.0067 g/L揭阳霉素处理,6天后校正虫口减退率为93.6%。     

深圳地区椰心叶甲寄主和天敌种类调查

调查结果表明,深圳地区椰心叶甲Brontispalongissima(Gestro)的寄主植物有26属36种,危害比较严重的寄主有椰子(CocosnuciferaL.)、大王椰子(RoystonearegiaO.F.Cook)、假槟榔(Archontophoenixalexandrae(F.V.Mueller))、鱼尾葵(CaryotaochlandraHance)、三药槟榔(ArecatriandraRoxburghexBuchanan)、金山葵(Syagrusromanzoffiana(Chamisso)Glassman)、菲岛鱼尾葵(CaryotacumingiiLoddigesexMartius)、刺葵(PhoenixhanceanaNaudin)、国王椰子(RavenearivularisL.)等。野外观察和采集标本鉴定结果表明,深圳地区椰心叶甲捕食性天敌有11种,主要种类为蚂蚁Formicasp.、毛蠼螋Cheatospaniasp.、中华大螳螂ParattenoderasinensisSaussure;致病微生物有3种,主要是绿僵菌Metarhiziumanisopliaevar.anisopliae。     

Infection and mortality of Microtheca ochroloma (Coleoptera: Chrysomelidae) by Isaria fumosorosea (Hypocreales: Cordycipitaceae) under laboratory conditions

Microtheca ochroloma Stål, the yellowmargined leaf beetle, is a pest in crucifer crops during the late fall and winter months in Florida. On organic farms, it is difficult to control due to the restricted use of insecticides, in addition to the lack of specific natural enemies. The objective of this study was to evaluate a blastospore-formulated product of Isaria fumosorosea (PFR-97^TM 20% WDG) against this beetle. In the first experiment, four of the beetle's life stages were treated with a suspension of 3 × 10⁷ blastospores/ml. Mean corrected mortality of treated insects was significantly higher in 1st and 3rd instars than in the egg, pupal, and adult stages. Larvae infected by I. fumosorosea exhibited reduced growth and unsuccessful molting. The second experiment quantified mortality of first instars of M. ochroloma by four concentrations of PFR-97^TM. Mean corrected larval infection/treatment was significantly (2.6 times) higher with a concentration of 4?g of product per 100?ml of water compared to concentrations of 1–3?g per 100?ml of water. Different factors that might have affected the pathogenicity of I. fumosorosea against M. ochroloma are discussed.     

五种芳香类挥发物质对酪蝇的引诱效果

室内采用Y-型嗅觉仪测定不同浓度(1.0×10-6,1.0×10-5,1.0×10-4和1.0×10-3mL/mL)水杨醛、水杨酸甲酯、苯乙醛、苯甲醛、桂醇5种化合物对酪蝇Piophila casei(L.)成虫的引诱效果。结果表明:1.0×10-6和1.0×10-5mL/mL苯乙醛,1.0×10-6mL/mL苯甲醛,1.0×10-5和1.0×10-4mL/mL水杨醛均对雌、雄虫表现明显的引诱效果。1.0×10-3mL/mL苯乙醛、水杨醛和苯甲醛对酪蝇雌、雄虫具有明显的驱避效果。桂醇和水杨酸甲酯在所测试的浓度范围内对雄虫具有明显的驱避效果。水杨酸甲酯在浓度为1.0×10-6mL/mL对雌虫有明显的引诱效果,其它浓度均对雌虫有明显的驱避效果。桂醇对雌虫有明显的驱避效果。这表明在高浓度时芳香物质对酪蝇成虫有驱避效果,在低浓度时对酪蝇成虫有引诱效果。     

The utilization of torula yeast in diets for White Leghorn birds during growth and laying periods

A total of 1440 one-day-old female White Leghorn birds was used in a 2 × 4 × 2 factorial experiment to evaluate the inclusion of torula yeast (grown on sugar cane final molasses) in grower diets for 0–6 weeks of age (0 and 20%), for 7–23 weeks (0, 6, 12 and 17%) and in laying hens' diets (0 and 18%). In the period 0–6 weeks of age, final live weight and feed conversion (465 and 444 g and 2.70 and 2.82) obtained with 0 and 20%, respectively, differed significantly (P < 0.05) but this had no effect on the later performance of the birds. For 7–19 weeks of age, average live weight gain (1143, 1119, 1093 and 1021 g/bird) was reduced by increasing the percentage of torula yeast in the diet, but conversion (4.43, 4.47, 4.48 and 4.72) increased significantly only with 17% torula. Torula yeast levels used for weeks 7–23 had no influence on subsequent egg production. The inclusion of 18% yeast during the laying period did not affect egg production (250 and 247 eggs/bird/year) nor egg weight (58.4 and 58.1 g) but increased consumption from 37.4 to 38.8 kg/bird/year. The results obtained suggest the possibility of including 20%, 17% and 18% torula yeast in diets for White Leghorn birds for weeks 0–6, weeks 7–23 and for laying hens, respectively.