Greenhouse-grown Horticultural Crops Research Articles

Are Entomopathogenic Fungal-based Insecticides and Insect Growth Regulator Mixtures Effective Against the Citrus Mealybug, Planococcus citri (Hemiptera: Pseudococcidae), Feeding on Coleus, Solenostemon scutellarioides, Plants under Greenhouse Conditions?

The citrus mealybug, Planococcus citri, is an insect pest of greenhouse-grown horticultural crops. Citrus mealybug causes plant damage when feeding on plant leaves, stems, flowers, and fruits, resulting in a substantial economic loss. Insecticides are applied to manage citrus mealybug populations in greenhouse production systems. Anecdotal information suggests that mixing entomopathogenic fungal-based insecticides with insect growth regulators may be effective for managing citrus mealybug populations under greenhouse conditions. Consequently, we conducted two experiments in a research greenhouse at Kansas State University (Manhattan, KS, USA) in 2023. The experiments were designed to determine the efficacy of three commercially available entomopathogenic fungal-based insecticides [Beauveria bassiana Strain GHA (BotaniGard®), B. bassiana strain PPRI 5339 (Velifer™) and Isaria fumosorosea Apopka Strain 97 (Ancora®)] when mixed with three insect growth regulators [azadirachtin (Azatin® O), novaluron (Pedestal®), and pyriproxyfen (Distance®)] on citrus mealybug feeding on coleus, Solenostemon scutellarioides, plants. The entomopathogenic fungal-based insecticides alone or when mixed with the insect growth regulators were not effective in managing citrus mealybug populations, with <20% mortality during each experiment. In addition, all coleus plants treated with the entomopathogenic fungal-based insecticides had a white, powdery residue on the leaves. Our study demonstrates that entomopathogenic fungal-based insecticides, even when mixed with insect growth regulators, are not effective in managing citrus mealybug populations in greenhouses, which is likely because the environmental conditions (temperature and relative humidity) are not optimal for conidial germination and hyphal infection to occur. Therefore, entomopathogenic fungal-based insecticides have limited use for managing insect pests in greenhouse production systems.

Hoverflies provide pollination and biological pest control in greenhouse-grown horticultural crops.

Beneficial insects provide pollination and biological control in natural and man-made settings. Those ecosystem services (ES) are especially important for high-value fruits and vegetables, including those grown under greenhouse conditions. The hoverfly Eupeodes corollae (Diptera: Syrphidae) delivers both ES, given that its larvae prey upon aphid pests and its adults pollinate crops. In this study, we investigated this dual role of E. corollae in three insect-pollinated and aphid-affected horticultural crops i.e., tomato, melon and strawberry within greenhouses in Hebei province (China). Augmentative releases of E. corollae increased fruit set and fruit weight of all three crops, and affected population dynamics of the cotton aphid Aphis gossypii (Hemiptera: Aphididae). On melon and strawberry, E. corollae suppressed A. gossypii populations by 54-99% and 50-70% respectively. In tomato, weekly releases of 240 E. corollae individuals/100 m2led to 95% fruit set. Meanwhile, releases of 160 hoverfly individuals per 100 m2led to 100% fruit set in melon. Also, at hoverfly/aphid release rates of 1:500 in spring and 1:150 in autumn, aphid populations were reduced by more than 95% on melon. Lastly, on strawberry, optimum levels of pollination and aphid biological control were attained at E. corollae release rates of 640 individuals/100 m2. Overall, our work shows how augmentative releases of laboratory-reared hoverflies E. corollae can enhance yields of multiple horticultural crops while securing effective, non-chemical control of resident aphid pests.

Performance of Entomopathogenic Fungal-Based Insecticides against the Citrus Mealybug (Hemiptera: Pseudococcidae) on Coleus (Lamiales: Lamiaceae) Plants under Greenhouse Conditions1

Abstract The citrus mealybug, Planococcus citri (Risso) (Hemiptera: Pseudococcidae), is an important insect pest of greenhouse-grown horticultural crops. Citrus mealybug causes direct plant damage when feeding on plant leaves, stems, flowers, and fruits, and this damage can result in substantial economic losses. Insecticides are used to manage citrus mealybug populations in greenhouse production systems. Although entomopathogenic fungal-based insecticides are labeled for use against citrus mealybug, there is no quantitative information on their efficacy against this insect pest under greenhouse conditions. Consequently, four experiments were conducted in a research greenhouse at Kansas State University (Manhattan) from 2020 to 2022 to determine the efficacy of three commercially available entomopathogenic fungal-based insecticides on citrus mealybug feeding on coleus, Solenostemon scutellarioides (L.) Codd (Lamiales: Lamiaceae), plants: Beauveria bassiana strain GHA (BotaniGard®, Laverlam International Corp., Butte, MT), B. bassiana strain PPRI 5339 (Velifer™, BASF, Research Triangle, NC), and Isaria fumosorosea Apopka strain 97 (Ancora®, OHP, Inc., Bluffton, SC). The surfactant polyether and polyether-polymethylsiloxane-copolymer (CapSil®, Aquatrols, Paulsboro, NJ) was added to spray solutions to determine whether the surfactant would enhance efficacy. The entomopathogenic fungal-based insecticides, with or without the surfactant, were not effective in managing citrus mealybug populations, with <50% mortality in all four experiments. Our study indicates that entomopathogenic fungal-based insecticides are not effective in managing citrus mealybug populations in greenhouses.

The Case for Sanitation as an Insect Pest Management Strategy in Greenhouse Production Systems

Abstract Protection of greenhouse-grown horticultural crops, including ornamentals and vegetables, from damage caused by insect pests involves implementing strategies such as insecticidal and/or biological control. However, cultural control may also mitigate plant damage caused by insect pests, as well as plant diseases including fungi and bacteria. An important cultural control is sanitation. Herein, we review the use and potential impact of sanitation practices as a part of an integrated pest management program for greenhouse production. These include removing weeds from inside and around the greenhouse perimeter, disposing of plant and growing medium debris from inside the greenhouse, and managing algae within the greenhouse. Weeds serve as alternate hosts for insects, such as aphids (Aphididae), whiteflies (Aleyrodidae), and thrips (Thripidae), that can spread plant viruses among greenhouse-grown horticultural crops. Sanitation practices that may reduce problems with weeds include installing geotextile fabric barriers underneath benches and on walkways, hand removal, mowing around greenhouse perimeters, and/or applying herbicides. Plant and growing medium debris serve as sources of insect pests, such as whiteflies, thrips, and fungus gnats (Sciaridae). Therefore, removal of plant and growing medium debris from within greenhouses and/or placement into refuse containers with tight-sealing lids before disposal may reduce problems with insect pests. Algae provides a habitat for fungus gnats and shore flies (Ephydridae) to breed. Overwatering and overfertilizing plants contributes to algae growth. Applying disinfectants or algaecides may mitigate problems with algae accumulating in greenhouses. In addition to reducing insect pest problems, sanitation practices may help reduce inputs from insecticide applications.

Spray Volume and Frequency Impacts on Insecticide Efficacy Against the Citrus Mealybug (Hemiptera: Pseudococcidae) on Coleus under Greenhouse Conditions

Abstract The citrus mealybug Planococcus citri (Risso) (Hemiptera: Pseudococcidae) is a major insect pest of greenhouse-grown horticultural crops. The citrus mealybug causes direct damage by feeding on plant leaves, stems, flowers, and fruits, which can lead to substantial economic losses. Consequently, insecticides are used to suppress citrus mealybug populations in greenhouse production systems. However, application factors may influence the efficacy of insecticides in suppressing citrus mealybug populations. Therefore, experiments were conducted under greenhouse conditions to determine the effect of spray volume and application frequency on insecticide efficacy against the citrus mealybug feeding on coleus, Solenostemon scutellarioides (L.) Codd, plants. Four spray volumes (15, 25, 50, and 75 mL), 2 application frequencies (1 or 2 applications), and 3 insecticides (acetamiprid [TriStar®], flonicamid [Aria®], and cyfluthrin [Decathlon®]), each with a different mode of action, were tested. Based on mean percent citrus mealybug mortality, acetamiprid was more effective against citrus mealybugs than flonicamid or cyfluthrin. In the spray volume experiments, acetamiprid applied at 75 mL to each plant resulted in a mean percent citrus mealybug mortality of over 70%. In contrast, flonicamid and cyfluthrin resulted in less than 50% mean citrus mealybug mortality across all experiments. In the application frequency experiments, two spray applications did not result in a significantly higher mean citrus mealybug mortality than one spray application. Our study emphasizes the importance of spray volume and application frequency when using insecticides to suppress citrus mealybug populations.

Effects of Spray Volume and Application Frequency on Insecticide Efficacy Against Adult Western Flower Thrips (Frankliniella Occidentalis) under Greenhouse Conditions

The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is a major insect pest of greenhouse-grown horticultural crops. Western flower thrips causes direct and indirect damage by feeding on plant leaves, flowers, and fruits, and by transmitting viruses that can result in greenhouse producers experiencing substantial economic losses. Consequently, insecticides are used to suppress western flower thrips populations. However, issues associated with applying insecticides may affect the suppression of western flower thrips populations. Therefore, experiments were conducted under greenhouse conditions to determine the effects of the spray volume applied and application frequency on insecticide efficacy against western flower thrips adults located in transvaal daisy, Gerbera jamesonii, cut flowers. Four spray volumes (5.0, 10.0, 12.5, and 25.0 mL), two application frequencies (one or two spray applications), and three insecticides [spinosad (Conserve), chlorfenapyr (Pylon), and flonicamid (Aria)], each with a different mode of action, were tested. The insecticide treatments had the greatest effects on the mean percent mortality of western flower thrips adults regardless of spray volume or application frequency. However, in Expt. 3, the 5.0- and 10.0-mL spray volumes resulted in a higher mean percent mortality of western flower thrips adults than the 2.5-mL spray volume. Spinosad and chlorfenapyr resulted in a mean percent mortality of more than 72% for western flower thrips adults, whereas flonicamid resulted in mean percent mortality between 40% and 91%. Our study demonstrates that certain insecticides are more effective against western flower thrips adults located in transvaal daisy flowers than others, which will help greenhouse producers effectively manage western flower thrips populations.

Entrapment of Bradysia paupera (Diptera: Sciaridae) by Phaseolus vulgaris (Fabaceae) plant leaf

Flies of the genus Bradysia (Diptera, Sciaridae) are considered as major insect pests of greenhouse-grown horticultural crops. The ability of hooked trichomes of the French bean Phaseolus vulgaris to impale and entrap herbivorous insects thus resulting in insect reduced longevity, reproduction and larval mortality is well known. The present study investigates under laboratory conditions the ability of hooked trichomes of bean leaves to entrap fungus gnats Bradysia paupera, in order to estimate the reduction of their population. We characterized the entrapment mechanism of hooked trichomes towards B. paupera using cryo-scanning electron microscopy, and evaluated the silicon distribution in hooked trichomes with the energy dispersive X-ray microanalysis. We evaluated the trapping efficiency of hooked trichomes in fertilized and unfertilized bean plants towards B. paupera, in comparison with insects feeding on the plant leaf such as black bean aphid Aphis fabae and young stages of the southern green stinkbug Nezara viridula. For B. paupera, we recorded about 30% of entrapped insects in unfertilized plants. Considering the number of entrapped insects in relation to the leaf surface, the percentage of entrapped insect was higher in unfertilized than in fertilized plants having lower density of hooked trichomes. The presence of P. vulgaris plants in greenhouses could represent a useful method in integrated pest management to reduce Bradysia spp. population.

Effect of Insecticide Drench Applications on Western Flower Thrips, Frankliniella occidentalis, Pupae in Growing Media

Western flower thrips, Frankliniella occidentalis, is one of the most destructive insect pests of greenhouse-grown horticultural crops. The primary method of managing western flower thrips populations involves applications of insecticides; however, there is no information associated with the effect of the insect growth regulator, pyriproxyfen, or the entomopathogenic fungus, Isaria fumosorosea, on western flower thrips pupae in growing media. Therefore, four laboratory experiments were conducted to determine the effect of pyriproxyfen and I. fumosorosea applied as a drench to growing media on western flower thrips pupae. Expt. 1 evaluated the efficacy of pyriproxyfen and I. fumosorosea on western flower thrips pupae. Based on the results from Expt. 1, Expt. 2 assessed the effect of pyriproxyfen in two growing media (LC1 and BM1) on western flower thrips pupae. Expts. 3 and 4 determined the residual activity of pyriproxyfen in growing media on western flower thrips pupae 3, 5, 7, and 14 days after treatments were applied. The pyriproxyfen treatment resulted in a significantly lower estimated mean probability of western flower thrips adults captured on yellow sticky cards (17%) compared with the water control (59%), untreated check (88%), and two I. fumosorosea treatments (46% for 1.0 g and 41% for 2.0 g of Ancora) in Expt. 1. However, for the two growing media in Expt. 2, the estimated mean probability of western flower thrips adults captured on yellow sticky cards was not significantly different between the pyriproxyfen treatment (LC1 = 15%; BM1 = 12%) and the water control (LC1 = 41%; BM1 = 24%). For either the pyriproxyfen treatment or the untreated check, there was no evidence of a significant difference between the two growing media on the estimated mean probability of western flower thrips adults captured on yellow sticky cards. Furthermore, there was no evidence of any residual activity 3 days after drench applications of pyriproxyfen. The results of the study have demonstrated that drench applications of pyriproxyfen are not affecting survival of western flower thrips pupae.

Effects of Predators on the Belowground Life Stages (Prepupae and Pupae) of the Western Flower Thrips, <i>Frankliniella occidentalis</i> (Thripidae: Thysanoptera): A Review

Western flower thrips, Frankliniella occidentalis, is a major cosmopolitan insect pest causing direct and indirect damage to greenhouse-grown horticultural crops. The primary way of managing western flower thrips populations is by routinely applying insecticides, which target the aboveground life stages: larvae and adult. However, insecticides are minimally effective against the pupal stages (prepupae and pupae) that reside in the growing medium or soil. Therefore, soil-dwelling biological control agents including: predatory mites [Stratiolaelaps scimitus and Hypoaspis = (Geolaelaps) aculeifer], and a rove beetle, Dalotia coriaria may be a viable option to induce mortality on the pupal stages. These predators will feed on the pupal stages of the western flower thrips and can provide mortality on a life stage that is tolerant of insecticide applications. However, these biological control agents need to be used in conjunction with other plant protection strategies, such as insecticides and/or biological control agents that target the aboveground life stages (larvae and adult) to effectively manage western flower thrips populations in greenhouse production systems.

Effect of Systemic Insecticides on the Citrus Mealybug (Hemiptera: Pseudococcidae) Feeding on Coleus

Abstract The citrus mealybug, Planococcus citri (Risso), is a major pest of greenhouse-grown horticultural crops. Systemic insecticides are often used by greenhouse producers in an attempt to prevent infestations or suppress citrus mealybug populations. However, minimal information is available on the efficacy of systemic insecticides against citrus mealybug populations when applied as a granule or water-soluble drench to the growing medium. We determined the efficacy of curative and preventative applications of six commercially available systemic insecticides against the citrus mealybug on coleus (Solenostemon scutellarioides [L.] Codd) plants. The systemic insecticides tested were imidacloprid, dinotefuran, thiamethoxam, azadirachtin, cyantraniliprole, and spirotetramat. The curative applications of dinotefuran, imidacloprid, and thiamethoxam resulted in citrus mealybug mortality that never exceeded 35%. Preventative applications of dinotefuran, imidacloprid, and thiamethoxam yielded only 50% citrus me...

시설 시금치와 상추의 특화 요인 분석

이 논문은 시설채소류의 특화계수와 특화에 영향을 미치는 요인들을 분석하였다. 이를 위해 2000년, 2005년, 2010년 농업총조사 자료를 이용하여 지역특화 계수를 도출하였다. 분석결과 시설 시금치와 상추의 특화정도가 심화된 것으로 나타났다. 즉 2000년 이후 시설원예 채소류의 지역별 특화정도가 강화되고 있다는 것을 알 수 있다. 또한 로짓분석을 통해 시설 시금치와 상추의 특화에 영향을 미치는 요인들을 분석하였다. 시금치의 특화에 영향을 미치는 요인들은 1인당 GRDP, 연령, 학력, 평균종사자수, 컴퓨터보유비율이 통계적으로 유의한 것으로 분석되었다. 즉 1인당 GRDP, 연령, 학력이 낮을수록, 평균 종사자수와 컴퓨터보유비율이 높을수록 시설 시금치가 특화되어 있는 것으로 분석되었다. 상추의 특화에 영향을 미치는 요인들은 1인당 GRDP, 학력, 생산자조직비율이 통계적으로 유의한 것으로 분석되었다. 즉 1인당 GRDP, 연령, 학력이 낮을수록, 생산자조직비율이 높을수록 시설 상추가 특화되어 있는 것으로 분석되었다. 시설 엽채류의 지역별 특화수준을 진단하고 경쟁력 강화를 위한 전략을 마련할 수 있을 것이다. 한편, 지역농정의 역량을 선택과 집중의 강령에 입각하여 지역농업 특화 전략을 전개하는 대책이 요망된다. This paper analyzes the specialization factors for greenhouse-grown horticultural crops and location quotient. We derived the location quotient of two crops from the Agricultural Census in 2000, 2005, and 2010. The location quotient shows that specialization factors for spinach and lettuce became more concentrated. This means that cultivation of vegetables lean too much towards specialized regions. Implementation policies based on the level of specialization is expected to more efficiently improve the competitiveness of regional agriculture. The logit analysis showed that GRDP, age, education, average employee, and ratio of computer use had a significant impact on specialization of spinach. GRDP, age, and education negatively affected the specialization coefficient of spinach. However, average employee, and ratio of computer use positively affected the specialization coefficient of spinach. Based on these results, we set up the policy tools specializing the regional location quotient.

Ecology and Role of the Rove Beetle, <i>Dalotia coriaria</i>, and Insidious Flower Bug, <i>Orius insidiosus</i>, in Greenhouse Biological Control Programs

Greenhouse production systems typically involve growing multiple crop types simultaneously, including ornamentals and vegetables. Therefore, greenhouse producers commonly deal with multiple pest complexes. Two important insect pests of greenhouse-grown horticultural crops are fungus gnats (Bradysia spp.) and western flower thrips (Frankliniella occidentalis). A plant protection strategy that can be used to manage both pests is biological control. The rove beetle (Dalotia coriaria) and insidious flower bug (Orius insidiosus) are generalist predators commercially available for use in greenhouse production systems targeting fungus gnats and the western flower thrips. This article describes the biology, behavior, ecology, and role of both natural enemies in greenhouse production systems, and discusses the direct and indirect effects of pesticides (insecticides, miticides, and fungicides) on D. coriaria and O. inisidiosus.

Western Flower Thrips (Thysanoptera: Thripidae) and Insecticide Resistance: An Overview and Strategies to Mitigate Insecticide Resistance Development

Abstract Western flower thrips, Frankliniella occidentalis (Pergande), are one of the most-destructive insect pests of greenhouse-grown horticultural crops worldwide due to the direct and indirect damage they cause to plants. Western flower thrips induce direct damage by feeding on leaves and flowers and also cause indirect damage by vectoring certain tospoviruses including Impatiens necrotic spot and Tomato spotted wilt viruses. As a result, the threshold for this insect pest is near zero. Consequently, the primary means of suppressing populations of western flower thrips in greenhouse production systems is the application of insecticides. In general, insecticides are inexpensive, easy to apply, and relatively effective. However, the selection pressure placed on western flower thrips populations due to intensive applications of insecticides has resulted in severe problems associated with the development of resistance. Therefore, in order to avoid the prospect of insecticide resistance developing in west...

Ecology of Fungus Gnats (Bradysia spp.) in Greenhouse Production Systems Associated with Disease-Interactions and Alternative Management Strategies.

Fungus gnats (Bradysia spp.) are major insect pests of greenhouse-grown horticultural crops mainly due to the direct feeding damage caused by the larvae, and the ability of larvae to transmit certain soil-borne plant pathogens. Currently, insecticides and biological control agents are being used successively to deal with fungus gnat populations in greenhouse production systems. However, these strategies may only be effective as long as greenhouse producers also implement alternative management strategies such as cultural, physical, and sanitation. This includes elimination of algae, and plant and growing medium debris; placing physical barriers onto the growing medium surface; and using materials that repel fungus gnat adults. This article describes the disease-interactions associated with fungus gnats and foliar and soil-borne diseases, and the alternative management strategies that should be considered by greenhouse producers in order to alleviate problems with fungus gnats in greenhouse production systems.

Efficacy of Binary Pesticide Mixtures Against Western Flower Thrips

This study was designed to determine the efficacy of binary pesticide mixtures against one of the most important insect pests of greenhouse-grown horticultural crops, western flower thrips (Frankliniella occidentalis). Two separate experiments were conducted under greenhouse conditions to simulate a greenhouse production cycle using yellow transvaal daisy (Gerbera jamesonii) cut flowers, which were artificially infested with a known number of western flower thrips. The pesticides used in the two experiments were spinosad, pymetrozine, abamectin, pyridalyl, fluvalinate, chlorfenapyr, bifenazate, azadirachtin, petroleum oil, tolfenpyrad, fenhexamid, azoxystrobin, and spirotetramat. Pesticide mixtures were evaluated at the recommended labeled rates (Expt. 1) and assessments were made to determine if adding didecyl dimethyl ammonium chloride enhanced the efficacy of the pesticide mixtures (Expt. 2). Results from Expt. 1 indicated that many of the binary pesticide mixtures provided ≥80% mortality of western flower thrips although this was a baseline population without previous exposure to pesticides. In Expt. 2, the addition of didecyl dimethyl ammonium chloride failed to increase the efficacy of most of the designated pesticide mixtures compared with the pesticides applied separately. Furthermore, none of the binary pesticide mixtures were phytotoxic to the transvaal daisy flowers. Although there are issues associated with using pesticide mixtures such as the potential for resistance developing to different pesticides in mixtures, greenhouse producers combine pesticides together to reduce labor costs and expand the spectrum of activity against insect and mite (Tetranychidae) pests. Therefore, the relevance of this information is that greenhouse producers now understand which pesticide mixtures may be used and those that should be avoided when suppressing populations of western flower thrips thus minimizing feeding damage to greenhouse-grown horticultural crops.

Effect of Fungicides and Miticides with Mitochondria Electron Transport Inhibiting Activity on the Twospotted Spider Mite, Tetranychus urticae (Acari: Tetranychidae)

The twospotted spider mite, Tetranychus urticae, is a major arthropod pest of many greenhouse-grown horticultural crops. Greenhouse producers use a variety of miticides to suppress twospotted spider mite populations. A group of miticides known as mitochondria electron transport inhibitors or METIs include acequinocyl, fenpyroximate, and pyridaben. In addition, there are strobilurin-based fungicides such as azoxystrobin, kresoxim-methyl, and trifloxystrobin that are also known as METIs. We conducted a study to determine if these METI fungicides had any miticidal properties against the nymph and adult stages of the twospotted spider mite. The designated treatments were applied to marigold (Tagetes erecta) plants naturally infested with twospotted spider mites. Assessments of live and dead twospotted spider mite nymphs and adults were conducted 3, 7, and 14 days after applying the treatments. None of the METI fungicides had any activity against the nymph and adult life stages of the twospotted spider mite, with percentage mortality values <18%. The METI miticides appeared to be more effective against twospotted spider mite nymphs than the adults based on percentage mortality values across the three evaluation periods (35.2% to 100% for nymphs and 11.4% to 87.9% for adults). This study demonstrated that the strobilurin-based fungicides have negligible negative effects on twospotted spider mites.

Briquettes of plant remains from the greenhouses of Almería (Spain)

Since ancient times, plant biomass has been used as a primary fuel, and today, with the impending depletion of fossil fuels, these vegetal sources constitute a cleaner alternative and furthermore have a multitude of uses. The aim of the present study is to design a method of recycling and reuse of plant wastes from intensive agriculture under plastic, by manufacturing briquettes in an environmentally friendly manner. In Almería (SE Spain), agriculture generates 769,500 t/year of plant remains from greenhouse-grown horticultural crops, a resource currently used for composting and for producing electricity.With the machinery and procedures of the present study, another potential use has been developed by detoxifying and eliminating the plastic wastes of the original biomass for the fabrication of briquettes for fireplaces. The results were slightly inferior to the commercial briquette from other non-horticultural plant materials (no forestry material), specifically 2512 kJ/kg, in the least favourable case. On the contrary, the heating value with respect to the two charcoals was significantly lower, with a difference of 12,142 kJ/kg. In conclusion; a procedure, applicable in ecological cultivation without agrochemicals or plastic cords, has been developed and tested to reuse and transform plant materials from intensive cultivation into a stable non-toxic product similar to composite logs, applicable in commercial settings or in residential fireplaces.