The relationship between morphological traits of the spring wheat spike and oviposition deterrence to orange wheat blossom midge

If morphological traits of a plant cause resistance to an insect pest or are strongly correlated with resistance levels, those traits can be used by plant breeders as phenotypic markers for indirect selection of resistance. To improve our understanding of antixenosis against the orange wheat blossom midge, Sitodiplosis mosellana (Géhin) (Diptera: Cecidomyiidae), expressed as oviposition deterrence in bread wheat, Triticum aestivum L. (Poaceae), 21 morphological traits of the wheat spike were studied in a genetically related wheat population and correlation of the traits with deterrence level was explored. The following traits had larger values in the deterrent parent of the population than the susceptible parent: ligule length, glume length, length of hair inside glume, palea length at post-anthesis stage, length of hair inside lemma, length of hair at spikelet base, inter-spikelet distance, and length of hair at rachis edge at post-anthesis stage. The highest correlation coefficient between mean egg density and a morphological trait of the wheat population was −0.287, which was for inter-spikelet distance. This represented 8% predictability from the point of view of crop breeding and explained one-twelfth of the variation in oviposition deterrence among lines. The morphological traits of bread wheat spikes were not highly correlated to deterrence. Therefore, no promising trait could be recommended for use in breeding programs. Studies of the fine-scale properties of the wheat plant surface, and their interactions with plant surface chemistry, with a greater focus on wheat midge oviposition behavior, may clarify the effect of the morphological traits on oviposition and deterrence.     

An interspersed refuge for Sitodiplosis mosellana (Diptera: Cecidomyiidae) and a biocontrol agent Macroglenes penetrans (Hymenoptera: Pteromalidae) to manage crop resistance in wheat

An interspersed refuge of susceptible plants in a resistant, spring-sown wheat crop was tested as a strategy to protect crop resistance against evolution of virulence by the wheat midge Sitodiplosis mosellana (Géhin), and also to conserve a biocontrol agent Macroglenes penetrans(Kirby). Eight replicated field experiments were conducted using seed mixtures of 0, 5, 10, 15 and 100% or 0, 5 and 100% susceptible wheat with an agronomically similar wheat expressing the antibiotic resistance gene Sm1. The frequencies of eggs, mature larvae and parasitized larvae in susceptible and resistant wheat spikes, and midge-affected seeds in the harvest, were recorded for each plot. In susceptible wheat, insect densities and seed damage were typical of those in commercial wheat. In resistant wheat, few larvae completed development, 2% or less compared with about 80% in susceptible wheat, when larvae were sampled at maturity. This resistant wheat also deterred midge oviposition, reducing egg densities by 65% compared with susceptible wheat. The wheat midge and its parasitoid oviposited throughout the plots, and parasitism was density independent. The densities of mature midge larvae and parasitoids were in proportion to the size of the refuge. A 5% susceptible refuge produced about 41 mature larvae for each mature larva from the resistant wheat, and provided effective control of damage. An interspersed refuge of susceptible plants in resistant wheat is a promising strategy for sustaining resistance conferred by Sm1 and biocontrol of the wheat midge.     

Sex ratios of Sitodiplosis mosellana (Diptera: Cecidomyiidae): implications for pest management in wheat (Poaceae)

Sex ratios of populations of the wheat midge Sitodiplosis mosellana Gehin, developing on wheat Triticum aestivum L., were determined at reproduction, adult emergence, and dispersal. The patterns of sex ratio through the life cycle of S. mosellana result from: (i) a genetic mechanism that causes all or nearly all of the progeny of individual females to be a single sex, with an overall sex ratio that is slightly biased at 54-57% females; (ii) a differential mortality during diapause that increases the sex ratio to 60-65% females; (iii) mating which occurs near the emergence site followed by female dispersal which causes the post-dispersal sex ratio to rise to nearly 100% females; and (iv) oviposition which spreads eggs among different plants and assures that the next generation has a local sex ratio close to the population average. These changes in sex ratio through the life cycle have implications for using crop resistance or pheromones to manage S. mosellana, because mating takes place quickly near emergence sites, and because mated females but not males disperse from emergence sites to oviposition sites. Crop refuges used to protect resistance genes against the evolution of virulence by S. mosellana must be interspersed to prevent assortative mating that would occur in separate blocks of resistant and susceptible plants. Monitoring or mating disruption using a pheromone would be ineffective when wheat is grown in rotation with a non-host crop.     

薇甘菊提取物对红脉穗螟的产卵忌避及杀卵作用

【目的】探讨入侵杂草薇甘菊Mikania micrantha对棕榈害虫红脉穗螟Tirathaba rufivena的产卵忌避活性。【方法】采用室内生物测定法,研究薇甘菊不同溶剂提取物对红脉穗螟的产卵忌避作用和杀卵活性。【结果】产卵忌避试验结果表明,薇甘菊各提取物中,以正己烷和三氯甲烷提取物对红脉穗螟的产卵忌避效果最好,两者的选择性忌避率分别为43.64%和44.20%,非选择性忌避率分别为51.60%和59.20%。对卵孵化率的影响显示,各溶剂提取物均对红脉穗螟具有一定的杀卵活性,其中三氯甲烷提取物对卵孵化率的影响最大,校正孵化率最低,仅为53.39%,而且三氯甲烷提取物引起的1龄幼虫的死亡率最高,可达42.64%。在薇甘菊三氯甲烷提取物的不同溶剂萃取物中,正丁醇萃取物对红脉穗螟的产卵忌避和杀卵活性均显著高于其他溶剂萃取物。【结论】薇甘菊提取物具有一定的产卵忌避和杀卵活性,具有用于红脉穗螟的生态防控的潜力。     

飞机草提取物对红脉穗螟的产卵忌避及杀卵活性

为探讨飞机草提取物对红脉穗螟Tirathaba rufivena Walker的防控潜力,采用室内生物测定法,研究了飞机草提取物对红脉穗螟的产卵忌避作用和杀卵活性。结果表明,飞机草乙酸乙酯提取物对红脉穗螟的忌避效果最好,选择性和非选择性忌避率分别为41.85%和46.84%;不同提取物处理红脉穗螟的卵后,均造成卵孵化率降低和初孵幼虫的死亡,其中乙酸乙酯提取物对红脉穗螟卵的影响最大,孵化率和1龄幼虫死亡率分别达到65.89%和40.37%。对飞机草乙酸乙酯提取物进行分级萃取测试各萃取物的活性发现,正己烷萃取物对红脉穗螟的产卵忌避作用和杀卵活性最强。田间试验表明,采用正己烷萃取物稀释50倍和100倍浓度进行田间喷雾,药后15 d对红脉穗螟的种群控制率可达到50%以上。     

小麦品种冀麦24抗麦红吸浆虫QTL分析

麦红吸浆虫是影响小麦产量和品质的重要害虫,研究小麦对吸浆虫抗性的遗传及其连锁分子标记对于提高抗虫品种的选择效率具有重要意义。本研究以小麦感虫品系6218与抗虫品种冀麦24产生的重组近交系(RIL)群体为材料,利用SSR标记和人工虫圃对冀麦24的抗虫性遗传进行了研究。结果表明:6218与冀麦24的抗性差异显著,RIL群体在2年2点的鉴定中抗性稳定;所构建的遗传连锁图谱包含112个SSR位点,形成26个连锁群,图谱全长835.7 cM,标记间平均距离为7.5 cM。利用QTL IciMapping的完备区间作图法,在4A染色体上检测到1个加性效应位点(QSm.hbau-4A),该位点在2个鉴定年度的贡献率分别为9.67%、10.57%。该抗性QTL及其连锁SSR标记的发掘,将有助于提高小麦抗吸浆虫育种的选择效率。     

Oviposition Deterrence Is Likely an Effect,Not a Mechanism,in the Leaf Beetle <Emphasis Type="Italic">Chrysophtharta bimaculata</Emphasis> (Olivier) (Coleoptera: Chrysomelidae)

Oviposition deterrence is common in many insects as an evolutionary mechanism to reduce subsequent larval competition. We investigated a suspected case of oviposition deterrence by the paropsine chrysomelid, Chrysophtharta bimaculata. In paired choice tests, gravid females were found to prefer ovipositing on host leaves without conspecific eggs, confirming the presence of an apparent oviposition deterrence mechanism. Washing egg batches in water, hexane, or ethanol did not change this preference, suggesting that a soluble marking pheromone was not involved. Furthermore, it is unlikely that a plant-derived oviposition deterring substance is produced as beetles showed no significant oviposition preference between leaves which had been oviposited upon, but then had the eggs removed, and those that had never been oviposited upon. In trials using artificial leaves and mimic egg batches, “leaves” with “egg batches” placed near the tip of the leaf (the preferred site of oviposition in this species) were significantly less likely to be laid upon than artificial leaves where mimic eggs were placed away from the tip. In combination, the results strongly infer that oviposition deterrence in C. bimaculata is due to the mechanical blocking of the oviposition site by the first laid egg-batch, rather than a specific oviposition deterring cue. The apparent oviposition deterrence in this insect may well be an outcome or evolutionary effect of oviposition-site selection, rather than a clear adaptive mechanism to decrease larval competition.     

Evaluation of oviposition deterrence in management of resistance to transgenic corn by European corn borer (Lepidoptera: Crambidae)

We modified an existing model for European corn borer, Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae), population dynamics and genetics to evaluate the effectiveness of oviposition deterrence in transgenic fields for resistance management. We simulated two types of deterrence: one type has females reducing their oviposition because of lost opportunities to lay eggs (eggs lost), and the other type has the deterred females moving to the refuge to lay eggs. Oviposition deterrence was clearly effective in extending the time to resistance to transgenic corn (R allele) in the European corn borer, particularly when 80% or more of the eggs were deterred from being oviposited on the transgenic plants. With 90% of eggs deterred, the time required to reach 50% R-allele frequency increases 3.7- to 5.5-fold compared with the no-deterrence scenario. The time to 50% R-allele frequency was similar for the two types of simulated deterrence, but the densities of the European corn borer were 100-fold higher when the deterred females oviposited in the refuge. The Y allele for insensitivity or resistance to deterrence never reached 50% within the 50-yr time line for these simulations except when the R allele was dominant and the Y allele was not recessive. The time to 50% Y-allele frequency was 33 and 26 yr when the Y allele was additive or dominant, respectively, when 50% of the eggs were deterred, but the time decreased to 18 and 16 yr when 90% of the eggs were deterred. The effectiveness of oviposition deterrence on time to resistance to transgenic insecticidal plants was not changed much when we altered our assumptions about behavior in a sensitivity analysis.     

麦红吸浆虫随气流远距离扩散的轨迹分析

为了解麦红吸浆虫Sitodiplosis mosellana (Géhin)种群随气流远距离扩散的可能性和扩散方向, 本研究于2010年5月在河南省洛阳市洛宁县, 利用系留气球携带取样器调查了麦红吸浆虫种群在5~75 m高空的分布以及活动节律, 应用HYSPLIT-4大气扩散模型模拟了2010年以洛宁县(34.35°N, 111.52°E)为起始点, 空中不同高度层麦红吸浆虫种群的扩散轨迹, 以及2007年麦红吸浆虫种群在我国北方麦区的扩散轨迹。结果表明: 在成虫发生期, 麦红吸浆虫在空中5, 45, 50和65 m 4个高度层种群密度较大, 表现出了明显的成层效应。2010年河南洛宁迁入的种群来自西南方的河南南阳地区, 迁出种群能够随气流进入东北方向的河南省宜阳县境内。2007年麦红吸浆虫种群能够随小麦发育期的先后, 随西南气流逐步向东北方向扩散。成虫随气流扩散是麦红吸浆虫种群远距离扩散的一种重要方式。研究结果有助于了解我国麦红吸浆虫远距离扩散方式, 同时对优化发生动态监测和综合治理提供参考。     

小麦吸浆虫空间格局参数及其应用

本文应用聚集度指数、分析表明了小麦吸浆虫在麦田中的空间格局呈负二项分布,并探讨了吸浆虫在田间的聚集原因以及小麦吸浆虫穗虫平均密度（ｘ）与负二项分布公共ｋｃ值的关系。     

Oviposition and feeding behavior of the maize borer,Chilo partellus,in response to eight essential oil allelochemicals

Eight essential oil compounds were evaluated against the maize borer, Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae), to determine their influence on oviposition and feeding behavior. Thymol was the most active compound against C. partellus when evaluated as an oviposition deterrent (ODI₅₀ = 1.36 mg ml^?1), an ovicide (LC₅₀ = 2.06 mg ml^?1), or a feeding deterrent (FI₅₀ = 141.8 μg cm^?2) in laboratory experiments. The results corroborated with greenhouse experiments, in which egg laying on maize plants was inhibited significantly when the treatment was 15 times the concentration used in the laboratory experiments. However, there was neither any correlation between oviposition deterrence and feeding inhibition, nor between oviposition deterrence and ovicidal action. Apparently, toxicity per se or ovicidal action does not play any role in choice of oviposition in C. partellus. This was more obvious when the efficacy of compounds was compared in greenhouse experiments where ODI values and number of eggs laid on the treated leaves did not differ significantly in choice and no‐choice situations. Apparently, toxicity plays an important role in predicting host plant choice, but behavioral response in terms of oviposition preference is independent of toxic action, particularly for non‐host toxins. Thus, the same compounds affecting oviposition behavior on the one hand and having ovicidal or feeding deterrent properties on the other could be useful in field situations in any area‐wide integrated pest management model.     

小麦品种（系）对麦红吸浆虫抗性指标筛选与抗性评价

【目的】筛选小麦对麦红吸浆虫Sitodiplosis mosellana抗性的准确鉴定方法, 明确生产上栽培小麦品种（系）对吸浆虫的抗性, 为抗虫小麦品种的筛选和利用提供科学依据。【方法】2012-2014年在陕西周至县建立麦红吸浆虫抗性鉴定圃, 调查并分析各参试小麦材料的估计损失率、粒被害率、穗被害率、单穗虫口和实际产量损失率及其相关性, 筛选出较准确的指标; 并以筛选到的指标为依据, 评估参试材料的抗性。【结果】估计损失率连续两年与其他3个抗性指标及实际产量损失率的相关性最强, 且均达到极显著水平。2012-2013年参试的85份和2013-2014年评估的80份材料中, 高抗、中抗和低抗材料合计分别为25份和40份; 重复种植的16份材料中, 14份两年均表现为抗性, 其中科农1006和晋麦47连续表现为高抗。【结论】估计损失率为具代表性且较准确的吸浆虫抗性鉴定指标。筛选出的抗性材料可作为抗吸浆虫的主推品种或后备品种, 也可作为亲本材料进行抗性育种研究。     

Identifications of two different mechanisms for sorghum midge resistance through QTL mapping

Sorghum midge is the one of the most damaging insect pests of grain sorghum production worldwide. At least three different mechanisms are involved in midge resistance. The genetic bases of these mechanisms, however, are poorly understood. In this study, for the first time, quantitative trait loci associated with two of the mechanisms of midge resistance, antixenosis and antibiosis, were identified in an RI (recombinant inbred) population from the cross of sorghum lines ICSV745 x 90562. Two genetic regions located on separate linkage groups were found to be associated with antixenosis and explained 12% and 15%, respectively, of the total variation in egg numbers/spikelet laid in a cage experiment. One region was significantly associated with antibiosis and explained 34.5% of the variation of the difference of egg and pupal counts in the RI population. The identification of genes for different mechanisms of midge resistance will be particularly useful for exploring new sources of midge resistance and for gene pyramiding of different mechanisms for increased security in sorghum breeding through marker-assisted selection.     

麦红吸浆虫在我国的发生、危害及防治

麦红吸浆虫Sitodiplosis mosellana是我国的一种重要农业害虫, 以幼虫危害小麦正在发育的籽粒, 可造成小麦严重减产, 甚至绝收。该害虫具有虫体小, 滞育时间长, 为害隐蔽等特点。近些年来, 受全球气候变化、 耕作制度改变、 小麦品种更换、 人类活动等多种因素的影响, 麦红吸浆虫在我国的发生危害情况发生了很大变化, 出现了北扩东移的现象。麦红吸浆虫主要分布在我国的北方麦区, 发生为害具有隐蔽性、 间歇性、 局部性和暴发性的特点。这种害虫的发生危害受虫源基数、 生态因子、 农业生产措施及人类活动等多种因素的影响。进入21世纪后, 麦红吸浆虫在我国的发生范围发生了很大的变化, 且主要分布在43°N以南到27°N以北的冬小麦主产区。有关麦红吸浆虫滞育的多态性、 小麦对麦红吸浆虫的抗性机理、 抗性品种的选育和天敌资源的开发等方面的研究将是今后的主要研究方向; 未来仍需加强对麦红吸浆虫滞育的分子机制、 发生危害规律、 预测预报、 综合防治和寄主植物 麦红吸浆虫 天敌三级营养关系等方面研究。本综述可为今后了解麦红吸浆虫在我国的发生危害规律、 预测预报及综合防治等提供参考。     

Antibiosis component of resistance in sorghum to sorghum midge, Contarinia sorghicola

Sorghum midge, Contarinia sorghicola Coq. (Diptera: Cecidomyiidae) is an important pest of grain sorghum, and host-plant resistance is one of the most effective means of controlling this pest. We studied the antibiosis mechanism of resistance in sorghum to C. sorghicola in a diverse array of midge-resistant and midge-susceptible genotypes. Data were recorded on adult emergence, postembryonic developmental period, number of mature eggs in the ovary, fecundity, larval survival from artificially implanted eggs; and the tannins, soluble sugars, and protein content of 10-day old and mature grains during the 1982-91 rainy and post-rainy seasons. Adult emergence was significantly lower in the midge-resistant genotypes compared with the susceptible controls. Initiation of adult emergence was delayed by 4–8 days on DJ 6514, IS 8571, IS 9807, IS 10712, IS 19474, IS 19512, ICSV 830 and ICSV 197. Postembryonic developmental period was prolonged on DJ 6514, IS 15107, IS 3461, IS 7005, IS 19474, ICSV 831 and ICSV 197. However, the delay in adult emergence or the extended developmental period was not observed during the post-rainy season in some genotypes. These differences in the expression of antibiosis to midge in resistant genotypes over seasons may be attributed to the effect of environmental conditions on the insect development and chemical composition of sorghum grain. Amounts of tannins and proteins were generally greater in the midge-resistant lines compared with the susceptible ones (except tannins in DJ 6514) while the soluble sugars were low in the midge-resistant lines (except TAM 2566). These differences in chemical composition of the grain between genotypes and variations over seasons have been discussed in relation to the expression of antibiosis mechanism of resistance to the sorghum midge. Antibiosis to sorghum midge was also evident in terms of smaller size of larvae, lower number of eggs in the ovary, reduced fecundity, and larval survival. Midge-resistant lines have diverse effects on the biology of this insect. Antibiosis along with other components of resistance can be used to develop cultivars with stable resistance to C. sorghicola.     

番茄抽提物对小菜蛾的忌避,拒食及抑制产卵作用

在自然变温条件下,研究了番茄抽提物对小菜蛾成虫的忌避、幼虫的拒食作用及成虫繁殖力的影响。试验表明：番茄抽提物对小菜蛾成虫具有很强的忌避作用;用番茄抽提物处理过的包菜叶饲喂小菜蛾幼虫,其拒食率达５３％;番茄提物对小菜蛾成虫产卵也有明显抑制作用,产卵量下降６０％;番茄与包菜间种能明显地抑制小菜蛾种群数量的增长。其种群可下降５０％以上。     

Mechanisms of Oryza sativa (Poaceae) resistance to Tagosodes orizicolus (Homoptera: Delphacidae) under greenhouse condition in Venezuela

Tagosodes orizicolus is one of the main plagues of rice in tropical America causing two types of damages, the direct one, feeding and oviposition effect, and an indirect one, by the transmission of the "Rice hoja blanca virus". During 2006-2007 we carried out research under greenhouse conditions at Fundaci6n Danac, Venezuela, in order to determine the mechanisms of antixenosis, antibiosis and tolerance to T. orizicolus, which could be acting in commercial varieties and advanced lines of the rice genetic breeding programs of INIA and Fundaci6n Danac. The method of free feeding was used for the antixenosis evaluation, whereas the method of forced feeding was used for antibiosis evaluation (effect on survival and oviposition). Additionally, we used the indirect method based on biomass depression to estimate the tolerance. Some of the evaluated traits included: grade of damage, number of insects settling on rice plants, percentage of sogata mortality at the mature state, number of eggs in the leaf midrib and an index of tolerance. The results showed that rice genotypes possess different combinations of resistance mechanisms, as well as different grades of reactions. The susceptible control 'Bluebonnet 50' was consistently susceptible across experiments and the resistant control 'Makalioka' had high antixenosis and high antibiosis based on survival and oviposition. The rest of the genotypes presented lower or higher degrees of antixenosis and antibiosis for survival and oviposition. The genotype 'FD0241-M-17-6-1-1-1-1' was identified with possible tolerance to the direct damage of sogata.     

Asymmetric evolution of egg laying behavior following reciprocal host shifts by a seed-feeding beetle

Colonization of new environments can lead to rapid changes in fitness-related traits. For herbivorous insects, switching to a new host plant can be comparable to invading a new habitat. Behavioral, physiological, and life-history traits commonly vary among insect populations associated with different plants, but how host shifts cause trait divergence is often unclear. We investigated whether experimental host shifts would modify a key insect trait, egg-laying behavior, in a seed beetle. Beetle populations associated long-term with either a small-seeded host (mung bean) or a large-seeded host (cowpea) were switched to each other’s host. After 36–55 generations, we assayed three aspects of oviposition behavior known to differ between the mung bean- and cowpea-adapted populations. Responses to the host shifts were asymmetrical. Females from lines transferred from mung bean to cowpea produced less uniform distributions of eggs among seeds, were more likely to add an egg to an occupied seed, and were more likely to “dump” eggs when seeds were absent. These lines thus converged toward the cowpea-adapted population. In contrast, the reciprocal host shift had no effect; oviposition behavior was unchanged in lines transferred from cowpea to mung bean. We suggest that these results reflect an asymmetry in the fitness consequences of each host shift, which in turn depended on differences in larval competitiveness in the original populations. Interactions among multiple fitness components are likely to make evolutionary responses less predictable in novel environments.     

不同抗性小麦品种上麦红吸浆虫幼虫的空间分布型与理论抽样数

【目的】为了解小麦品种抗性对麦红吸浆虫Sitodiplosis mosellana(Géhin)幼虫在麦穗上空间分布型的影响,为科学调查提供合理的抽样依据。【方法】2015年5月采用剥穗调查法对陕西省周至县试验田种植的4个抗虫和4个感虫小麦品种麦红吸浆虫幼虫危害进行调查,应用6种聚集度指标和Iwao M*?m回归法综合分析了幼虫在抗性不同小麦品种上的的空间分布结构。【结果】幼虫在抗、感小麦品种整穗及麦穗上、中、下部位上空间分布型一致,均呈聚集分布,但在抗虫品种上聚集强度大于感虫品种;抗、感小麦品种上分布的基本成分均为个体群,个体间相互吸引。聚集均数λ分析表明,幼虫在抗性较强品种上的聚集主要由小麦穗部化学物质和形态结构等环境因素引起,感虫品种上则由环境因素和成虫的产卵习性共同作用所致。幼虫在抗、感小麦品种上的发生趋势一致,均是上部发生最重,中部次之,下部最轻。根据Iwao回归法中的分布型参数,确立了幼虫在不同虫口密度和允许误差条件下的理论抽样数。【结论】麦红吸浆虫幼虫在抗性不同小麦品种上均呈聚集分布,调查时应根据当地栽培品种平均虫口密度选择适宜的抽样数量。     

Oviposition deterrence of shoots and essential oils of Minthostachys spp. (Lamiaceae) against the potato tuber moth

Abstract:  The potato tuber moth is a noxious pest of potato in stores, where the use of repellent plants is an environmentally sound alternative to the application of chemical pesticides. We evaluated the protective effect of native Minthostachys species (Lamiaceae) against tuber infestation by the potato tuber moth in a rustic store in Cusco, Perú. We covered potato tubers with dried shoots of Minthostachys spicata and Minthostachys glabrescens and compared tuber damage with a control treatment of maize straw. We also conducted a no-choice oviposition bioassay in the laboratory, testing the oviposition deterrence of essential oils of M. spicata , M. glabrescens and Minthostachys mollis at natural concentrations. We recorded the number of eggs laid by mated moths on filter paper treated with essential oils of each of the three species and on two control treatments: hexane and untreated blank. Finally, we tested for differences in oviposition deterrence among five full-sib families of potato tuber moth raised under identical conditions. We found that dried, chopped leaves and flowers of Minthostachys species reduced the percentage of tuber damage in stores in comparison with the control (5% vs. 12%), but no difference in protection was found between species. Essential oils at natural concentrations deterred moth oviposition, reducing the number of eggs laid by about 80% compared with the control treatments; again, there were no significant differences between Minthostachys species. Finally, whereas we detected among-family variation in oviposition on filter papers treated with essential oils, no difference was found in the number of eggs laid on control substrates. Therefore, there was genetic variation for oviposition deterrence in the potato tuber moth and resistance to repellent plants might evolve thereafter.