Prays Citri Research Articles

The first appearance of the citrus flower moth (Prays citri(Millière, 1873)) (Lepidoptera: Praydidae) in Lithuania

The first appearance of the citrus flower moth (Prays citri(Millière, 1873)) (Lepidoptera: Praydidae) in Lithuania

New observations and notes of Prays citri Millière, 1873 in Hungary (Lepidoptera: Praydidae)

New observations and notes of Prays citri Millière, 1873 in Hungary (Lepidoptera: Praydidae)

New observations and notes of Prays citri Millière, 1873 in Hungary (Lepidoptera: Praydidae)

The paper presents new data on observations of Prays citri Millère, 1873 in Hungary. It is found in large glass houses and in grass gardens. Professionals working there had not recognized the species. The author identified it by genital examination. In his opinion, the species may be present in several private nurseries where citrus fruits are kept in containers during the growing season and then moved to a warm place to escape winter frosts. Many citrus shipments arrive in Hungary from Mediterranean countries, so it is important to monitor Prays citri and organise its control. The study is illustrated with 17 figures.

Ecological and Biological Studies on the Citrus Flower Moth Prays citri (Millière) (Lepidoptera: Hyponomeutidae) in Qalyubia Governorate, Egypt

The investigation was carried out during two years in citrus orchards in Qalyubia Governorate 2015 – 2016, to study ecological and biological aspects of the Citrus Flower Moth Prays citri (Milliere) (Lepidoptera: Hyponomeutidae). Data illustrated from ecological and biological points of view. Ranjpure lime (Citrus auranifolia) was the most preferred variety (highly susceptible) of infested by P. citri. While lemon (Citrus limon) which is considered as “moderately susceptible” exhibit less preferable to P. citri, but not seen any infested flowers in navel orange (Citrus sinensis) was the lowest preferred variety, throughout the investigation 2015 – 2016. One peak of infestation of P. citri in spring under weather conditions of Qalyubia Governorate. Predatory potential of Chrysoperla carnea (Steph) larvae on citrus flower moth P. citri larvae, under laboratory conditions was highly significant in mean consumption rate of 2nd and 3rd instars The total consumption by the third instar of C. carnea was significantly than the second instar . Biological results indicated that Female laid eggs both individually 54.6 eggs in average per female, Incubation period lasted 1.07 days, hatchability was 67.7 % in average, Larval and pupal stage period was 6.37 and 5.33 days respectively, female and male longevity lasted 4.3 and 3.6 days respectively. Life cycle 12.77 days while Generation lasted 13.79 days under 29.4°C and 62.7 % RH.

Ecological and Biological Studies on the Citrus Flower Moth, Prays citri (Millière) (Lepidoptera: Hyponomeutidae).

The present investigation indicated that the citrus flower moth, Prays citri (Milliere) showed that differences in their response to host plant species. However, P. citri population greatly preferred lime over navel orange and mandarin. Lime flowers received the highest numbers of P. citri throughout the whole period of investigation, while no infestation occurred on mandarin. Navel orange flowers were of intermediate rank for P. citri population. The obtained results illustrated that both larval and pupal populations exhibited one peak of seasonal abundance during 2015 and 2016 seasons. Distribution of P. citri population within host plants, based on the analysis of variance, was affected by directions. However, P. citri population was significantly higher at the south direction than the other cardinal directions (north, west and east) and center of the canopies. The present study showed that P. citri population exhibited positive response to the increase of mean temperature, while, it showed negative response to both relative humidity and wind speed. No significant differences were observed between the duration periods of all developmental stages which reared on different host (lime, navel orange and mandarin) flowers. Analysis of life table of P. citri population indicated that mortality of larval stage is the Key-stage mortality, which can induce population changes comparing to other specific stage mortalities.

Pest risk assessment made by France on Prays citri considered by France as harmful in French overseas departments of French Guiana, Guadeloupe and Martinique - Scientific Opinion of the Panel on Plant Health

Pest risk assessment made by France on Prays citri considered by France as harmful in French overseas departments of French Guiana, Guadeloupe and Martinique - Scientific Opinion of the Panel on Plant Health

Rearing of Prays citri on callus derived from lemon stigma and style culture

A new method for rearing the citrus flower moth (Prays citri Mill.) (Lepidoptera, Yponomeutidae) on lemon [Citrus limon (L.) Burm.] callus is reported. In the present research callus (an undifferentiated mass of plant cells that can be grown under sterile conditions on an artificial medium in vitro) was induced from lemon stigma and style explants cultured on Murashige and Skoog (MS) medium supplemented with 500 mg l -1 malt extract, 13.3 μM 6-benzylaminopurine, and 146 mM sucrose. Also somatic embryogenesis and plant regeneration were obtained from the cultures of styles and stigmas of lemon. Adults were obtained from larvae on infested flowers collected in the field. Different oviposition substrates were used: white oval pearls (WOP), black oval pearls (BOP), rooted shoots (RS) of lemon obtained in vitro, and artificial flowers containing lemon callus (AF). Larvae were reared on lemon callus. Adults oviposited on RS, on WOP, and on AF. BOP were rejected as oviposition substrates. The flower moth reared on callus oviposited fertile eggs. In our tests P. citri completed three generations on callus or on callus plus shoots. In the latter case the larvae preferred callus and fed on shoots only after callus was completely eaten. The life cycle on callus at 23 ± 1 °C lasted about 21 days. There were significant differences between oviposition substrates for what concerns the number of eggs laid. It was observed that females generally preferred WOP (about 25 eggs/female) to AF (about 20 eggs/female) or RS (about 12 eggs/female) as oviposition substrate. Nevertheless the percentage of eggs that developed into adults was higher when AF sealed with stretched Paratilm were used (about 70% of eggs developed into adults). The method of rearing P. citri with AF was labour-saving and the feeding substrate (callus) had less tendency to become mouldy or decompose than when WOP and RS were used. Since such a diet is available for the insect all year round and callus can be produced in unlimited quantity, it could be possible to obtain a mass production of this moth.

Laboratory evaluation and field application of bacterial and fungal insecticides on the citrus flower moth,Prays citri miller (Lep., hyponomeutidae) in lime orchards in Egypt

The efficacy of two commercial products of Bactospeine and Bio-fly onPrays citri of lime trees was studied under laboratory and field conditions throughout the two seasons of 1996 and 1997. Laboratory results indicated that the pathogenic effect of Bactospeine,Bacillus thuringiensis (Berliner) was higher than that of Bio-fly,Beauveria bassiana in spite of the latter was applied with higher doses. Bactospeine at the rate (2 cc/1 l.w.) effected on the larvae more than on the adults, that treatment reduced no. of eggs/female by 81.70% and decreased the larval infestation by 90.08%. Bio-fly at the highest concentration (4 cc/1 l.w.) reduced the infestation with the eggs, the larvae and the pupae by 65.83%, 68.45% and 72.55%, respectively. Advanced effects of bacterial and fungal treatments on the final reduction rates ofP. citri infestation were recorded. Field applications revealed that two sprays with Bactospeine or Bio-fly gave good control ofP. citri more than one spray. Bactospeine at the rate (2 cc/1 l.w.) and Biofly at the rate (4 cc/1 l.w.) reduced the infestation by (89.82–93.43%) and (76.32–78.83%), respectively. In all cases, higher doses of bioinsecticides produced potentiation effects of infestation reduction. It is recommended that two sprays of Bactospeine at a rate (2cc/1 l.w.) are adequate effective to reduce the population of P. citri in lime orchards during the main flowering period of trees without need of chemical insecticides.

Bionomics of Prays citri (Lepidoptera: Yponomeutidae) and their use in a model of control by male mass trapping*

Abstract. 1. The paper describes the population dynamics of Prays citri (Milliere), relevant to the control of this pest by synthetic pheromone, as well as infestation of lemon trees in various areas and seasons.2. The responses of males to natural and synthetic sex pheromones are compared, and ratios for the degree of attraction of traps compared with the degree of attraction of competing wild females are calculated.3. The ratios obtained with various population densities over two seasons of the pest's activity are presented.4. The data are used in a model simulating control of Prays citri by male mass trapping.

Further field trials of pheromone dispensers and traps for males of Prays citri (Millière) (Lepidoptera: Yponomeutidae)

AbstractDispensers made of different materials and loaded with the female sex pheromone, (Z)-7-tetradecenal, were field-tested for attractancy for males of Prays citri (Mill.) in Israel. Hollow fibres of low density polyethylene, low density polyethylene chips and natural rubber septa were better than hollow fibres of polypropylene, hollow fibres of a polypropylene-polyethylene mixture, solid fibres of low density polyethylene and PVC tubes. In other tests, funnels with wall angles of 60° were inferior to those with angles between 70 and 80°; polyester funnels were superior to polystyrene and polypropylene ones, which were better than those of PVC or opalin coated with aluminium foil. Kaolin or talcum powder dusted on the inside walls improved the efficiency of polypropylene funnels. The catches in traps consisting of several plastic funnels or tubes under a roof and with insecticide to prevent escape did not differ significantly from those in the sticky traps. A modified version of a new trap with a renewable sticky floor is described; this and the funnel traps are at present the most useful and practical for catching P. citri males.

Field evaluation of the synthetic female sex pheromone of the citrus flower moth,Prays Citri (mill.) (Lepidoptera: Yponomeutidae), and related compounds

The synthetic female sex pheromone ofPrays citri, (Z)-7-tetradecenal, proved to be highly attractive to male moths in the field when released from a variety of dispensers in five different designs of sticky trap. When the pheromone was released from impregnated polyethylene vials, a wide range of initial loadings from 10 μg to 20 mg was attractive, and loadings of 40 μg and above were more attractive than a virgin female moth. Initial loadings of 0.5 mg and 1.0 mg remained attractive for at least five months in the field. Release rates of pheromone from the polyethylene vials under constant laboratory conditions were measured for two different initial loadings. Other isomers of the pheromone and a pheromone ‘mimic’, (Z)-5-dodecenyl formate, were unattractive to male moths and did not affect the attractiveness of the synthetic pheromone or of a virgin female moth.

Identification and synthesis of the female sex pheromone of the citrus flower moth, Prays citri

The female sex pheromone of the citrus flower moth, Prays citri, has been identified as (Z)-7- tetradecenal . The unusually small amounts of pheromone which could be extracted from the female moth precluded identification by classical methods. Instead, the basic structure of the pheromone was deduced from its gas chromatographic (GC) behaviour using a male moth prepared for electroantennographic (EAG) recording as detector; double bond position and geometry were determined by high resolution GC of the natural pheromone and a range of tetradecenal isomers, and by recording male moth EAG responses to these isomers. Synthetic (Z)-7- tetradecenal was shown to be highly attractive to male Prays citri when tested in citrus groves in Israel. This is the first reported identification of the female sex pheromone of a member of the Yponomeutidae.

The citrus blossom midge,Contarinia Citri Barnes (Diptera: Cecidomyiidae), in Israel

The citrus blossom midge,Contarinia citri Barnes, was sampled in two lemon groves. Infestation lasted from December through April. Midge-infested blossoms were seldom concomitantly attacked by the citrus flower moth,Prays citri Mill. Some midge larvae completed their development in the laboratory, their numbers declining and the period required for pupation becoming shorter toward the end of the season. Very few parasitoids were obtained. It is suggested thatC. citri andP. citri may be partially mutually-exclusive in lemon flowers, that the number of annual midge generations depends on the availability of blossoms, and that the midge may undergo a prolonged diapause in the soil.

Field and laboratory studies on sexual attractiveness of females of Prays citri (Mill.) (Lep., Yponomeutidae)

AbstractIn laboratory experiments with Prays citri (Mill.) in Israel, females 1–16 h old proved more attractive to 2–6-day-old males than did female pupae 1–8 h before emergence or female adults 1–4-days old. Attractiveness in the field was tested by means of sticky traps baited with female pupae or adult females. Females were attractive for up to 14 days in summer (19–30°C) and 27 days in winter (8–20°C). Greatest attraction was shown by 1–7-day-old females during summer as compared with 5–9-day-old females during winter. Field experiments with baited sticky traps attached to wind vanes showed that more males were caught by traps aligned with the wind than by those placed at right-angles to it or hung among tree branches, by traps 1–7 m above ground than those 30–50 cm above, and by traps five metres distant from trees than those 10–80 m distant.

Feeding, Development, and Reproduction of Amblyseius largoensis1 on Various Food Substances

Laboratory experiments were conducted on the reproduction and development of the predaceous mite Amblyseius largoensis Muma when offered various food substances. The young instars developed well and adults reproduced readily on Brevipalpus phoenicis (Geijskes), Eutetranychus orientalis (Klein), Tetranychus cinnabainus (Boisduval), on eggs of 2 moth species, Prays citri Milliere and Ectomyelois ceratoniae (Zeller), on nymphs and pupae of Retithrips syriacus Mayet, on a nematode, Panagrellus sp., and on the pollen of Carpobrotus acinaciformis (Mesembryanthemum) . Although A. largoensis developed on the honeydew of Planococcus citri (Risso) and Toxoptera aurantii (Fonscolombe), but poorly on Phyllocoptruta oleivora (Ashmead), reproduction was low on both P. citri honeydew and P. oleivora , and completely absent on T. aurantii honeydew. Similarly the predators succeeded in developing on scale crawlers of Aonidiella aurantii (Maskell) and Chrysomphalus aonidum (L.) and on pollen of citrus and Zea mays (corn); again, except for Z. mays , reproduction was low. In experiments on the effect of light on the rate of reproduction during mass rearing of the mites on Z. mays and C. acinaciformis , it was found that natural light produced the highest reproduction rate on both species. The possible significance of these responses is discussed in relation to the potential of A. largoensis to control citrus pests in the orchard.