Chromatomyia Horticola Research Articles

The influence of food supply on the parasitoid against Plutella xylostella L. (Lepidoptera: Yponomeutidae) on the longevity and fecundity of the pea leafminer, Chromatomyia horticola (Goureau) (Diptera: Agromyzidae)

The influence of food supply on the parasitoid Cotesia plutellae regarding the survival and reproductive potential of a non-target pest, pea leafminer Chromatomyia horticola, was examined in the laboratory. The male longevity of the leafminer dramatically increased when sugar or honey was available. On the other hand, sugar- or honey-fed females lived shorter lives than those fed on the host plant. Lifetime copulation times of the males were increased by their food supply. The lifetime fecundity of a pair significantly increased sugar or honey was supplied. This phenomenon was mainly explained by the positive relationship between the fecundity and the copulation count of females. We discuss the risk of an additional food supply increasing the numbers of non-target pests.

Liriomyza spp.

<i>Liriomyza</i> spp.

Faunistic Study of the Agromyzidae (Diptera) on Weeds of Marginal Areas in Northern Italy Agroecosystems

Extensive surveys of weedy plant species among hedgerows of different complexity and floristical composition were conducted with the aim to evaluate the role of weeds as reservoirs of agromyzids and to study the trophic relationships between these Diptera and noncrop plants. Field samplings were carried out weekly collecting foliage infested by leafminers from the representative weedy plants in three sites located in Bologna province, Italy. During 1998–1999, a total of 646 agromyzid specimens were reared, representing eight genera and 24 species. The most abundant species were Chromatomyia horticola (Goureau), Phytomyza lappae Goureau, Phytomyza ranunculi Schrank, Phytomyza plantaginis Robineau-Desvoidy, Liriomyza trifolii (Burgess), and Ophiomyia pulicaria (Meigen). C. horticola was the dominant species accounting for 35.76% of adults reared. Agromyzids mined 25 plant species belonging to nine families. The Asteraceae, in particular Cirsium arvense (L.) Scopoli and Sonchus asper (L.) Hill, were the most important sources of leafminers considering both species richness and population densities. Shannon–Weaver (H′), Simpson (D), and Berger–Parker (d) indices all pointed out that agromyzid species diversity was higher in the site characterized by the highest floristic richness, the highest complexity of ecological net and nonintensive agriculture. Most of the weeds sampled proved to be reservoirs for noneconomically important agromyzids in open-field crops in Italy.

Chalcidoid parasitoids of Chromatomyia horticola (Gour.) (Dip. Agromyzidae) in Sivas Province, Turkey

Chromatomyia horticola (Goureau, 1851) (Diptera Agromyzidae) is a polyphagous species and very common worldwide. In this study, parasitoids of Chromatomyia horticola were investigated on various plants during 2003 in the Sivas province. Infested leaves were sampled weekly and kept in the laboratory to observe and count emerging leafminers and parasitoid adults. Eight parasitoid species were reared belonging to Eulophidae and Pteromalidae (Chalcidoidea). Diglyphus iseae (Walker), Pediobius metallicus (Nees) and Diglyphus pachyneurus Graham represent the predominant parasitoid species. Among the parasitoids reared, Aprostocetus flavifrons (Walker), Merismus sp., and Chrysocharis crassiscapus (Thomson) have been newly recorded in Turkey and Aprostocetus flavifrons, Chrysocharis crassiscapus, Diglyphus pachyneurus Graham, and Merismus sp. were recorded for the first time from C. horticola.

Australian species of the genus Opius Wesmael (Hymenoptera: Braconidae) attacking leaf‐mining Agromyzidae, with the description of a new species from South‐east Asia

Abstract The species of Opius Wesmael that attack leaf‐mining Agromyzidae in Australia are discussed, and a key provided for their separation. Opius cinerariae Fischer is redescribed based on specimens reared from Liriomyza chenopodii (Watt) (Agromyzidae), and its subgeneric placement is discussed in light of newly discovered morphological features. Opius (Opiothorax) chromatomyiae Belokobylskij &amp; Wharton sp. n. is described from specimens reared from Chromatomyia horticola (Goureau) and Liriomyza huidobrensis (Blanchard) (Agromyzidae) in Malaysia, Indonesia and Vietnam. Opius insulicola Tobias nom. n. is proposed for Opius insularisTobias (1998), a junior primary homonym.

Insecticide susceptibility of the leafminer, Chromatomyia horticola (Goureau) (Diptera: Agromyzidae)

To clarify the reason for the recent dramatic outbreak of the leafminer, Chromatomyia horticola (Goureau), on the green pea in Japan, the insecticide susceptibility of two leafminer populations collected from grower's pea fields in Shizuoka and Kagoshima Prefectures was measured in a laboratory assay. Of the five insecticides registered for leafminer control on the pea, cartap was moderately effective, but phenthoate, malathion, permethrin and tralomethrin were less effective on larvae of the leafminer populations at their recommended dilutions. The leafminer population from Shizuoka was slightly less susceptible than the population from Kagoshima to all insecticides tested by LC50 assay. Emamectin-benzoate, fipronil, spinosad, chlorfenapyr, cyromazine and isoxathion were very effective in controlling leafminer populations. The impact of insecticide applications on the leafminer and associated parasitoids in pea fields in Shizuoka Prefecture was also discussed. Of the four samples of pea shoots collected from three fields, two samples collected one month after insecticide application had very few leafminers and many parasitoids. However the sample taken immediately after insecticide application had a very large number of emerged adult leafminers, but few parasitoids. The results suggest that the recent large outbreak of C. horticola might have resulted from a combination of low susceptibility to insecticides in the species and the destruction of the parasitoid complex due to frequent insecticide applications.

Insecticide susceptibility of the garden pea leafminer, Chromatomyia horticola (Goureau) (Diptera: Agromyzidae)

The insecticide susceptibility of the garden pea leafminer, Chromatomyia horticola (Goureau), on garden pea, Pisum sativum L. was evaluated at 25°C under a 15L-9D photoperiod. Among 21 tested on second stadium larvae using the leaf dipping method, isoxathion, chlorpyrifos, cartap, thiocyclam, ethofenprox, cypermethrin, emamectin benzoate, spinosad, tolfenpyrad, and milbemectin produced high mortality. Adults of C. horticola were highly susceptible to isoxathion, chlorpyrifos, thiocyclam, ethofenprox, emamectin benzoate, and pyridalyl.

The occurrence of leafminers and their parasitoids on vegetables and weeds in Hangzhou area, Southeast China.

Leafminers are the mostimportant insect pests of vegetables inHangzhou area, Zhejiang province, SoutheastChina as well as in the rest of China, but havenever been investigated for speciescomposition, relative abundance and theirassociated parasitoids. A survey was conductedin four localities of Hangzhou area during 1998–2000to determine the distribution ofleafminers and their parasitoids on vegetablecrops and weeds in the field. Over 20,000leafminers were collected and reared. Theleafminer species found were Liriomyzasativae, L. chinensis and Chromatomyia horticola, with C.horticola and L. sativae the mostabundant in spring and autumn, respectively.About 11,000 parasitoid adults were reared fromthe leafminers collected. In total 14hymenopteran species of four families (onebraconid, 10 eulophids, one megaspilid and onepteromalid) were found. Eleven species werereared from C. horticola, nine from L. sativae and seven from L. chinensis.Opius caricivorae and Chrysocharispentheus were the dominant species. Sevenspecies were recorded from L. chinensisfor the first time. Eleven parasitoid specieswere reared from leafminers on two weeds (Veronica undulata and Sonchusoleraceus). Parasitoids caused 48.5–68.8%parasitism on leafminers on crops and 83.7%parasitism on leafminers on weeds in the latergrowing season of vegetable crops. The resultssuggest that leafminer populations areregulated to a certain extent by their naturalenemies in the field.

Description of Chorebus denticurvatus sp. nov. and the Exuviae of Its Final Larval Instar (Hymenoptera: Braconidae: Alysiinae)

The imago and exuviae of the final larval instar of a new species of Dacnusini found in Spain are described and drawn: Chorebus denticurvatus sp. nov., an endoparasitoid of Chromatomyia horticola (Goureau). The morphological structures of phylogenetic value are discussed and keys are offered for the determination of the imagines.

Leafminers in vegetables, ornamental plants and weeds in Indonesia: Surveys of host crops, species composition and parasitoids

Extensive surveys of vegetable, ornamental and weedy plant species were conducted in highland and lowland vegetable production areas in Indonesia with the aim of recording leafminer species present and their associated natural enemies. The most common dipterous species reared from samples was the pea leafminer, Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae). This introduced pest was particularly serious in highland vegetables in Java, Sumatra and South Sulawesi, causing yield losses as high as 60-70%. Another alien species, the vegetable leafminer, Liriomyza sativae Blanchard, contributed to problems in lowland areas on the north coast of West Java, where cucumbers were heavily damaged. An Asian leafminer species, Chromatomyia horticola Goureau, was more common in snow peas (Pisum sp.). Intensive sampling of leafminer-infested leaves from surveyed host plants yielded 11 species of hymenopteran parasitoids: 10 eulophids (Asecodes sp., Chrysocharis sp., Cirrospilus ambiguus (Hansson and LaSalle), Closterocerus sp., Hemiptarsenus varicornis (Girault), Neochrysocharis formosa (Westwood), Neochrysocharis sp., Pnigalio sp., Quadrastichus sp., Zagrammosoma sp.) and 1 eucoilid (Gronotoma sp.). The most abundant parasitoid species was H. varicornis. Levels of parasitism varied among crops and growing seasons, but were usually low, especially on potato (< 3%). Surveys revealed that most farmers (63%) attempted to control leafminers by applying insecticides twice weekly although these applications were neither effective nor economical according to responses of about 72% of the farmers. An integrated pest management approach is suggested that emphasizes IPM training for vegetable farmers and includes reductionor elimination of broad spectrum chemicals that would adversely affect parasitoids that may already be present as well as those that may be introduced. The initiation of a classical biological control programme is recommended to enhance the limited parasitoid complex present in Indonesia and increase levels of biological control.

Separation of Agromyzidae species and populations associated with legumes using discriminant analysis

Agromyzidae populations occurring in legumes in Kenya were tested for speciation at host-type level and at the species level using discriminant analysis. Measurements were taken of various morphological characters of five populations of Chromatomyia horticola from five host plants and of seven male and female agromyzid species. The ratio of the proximal to the distal part of the wing vein, (M 3+4 ) provided the best discrimination for five host populations of C. horticola; the species was separated into two distinct groups by this character. Females of Ophiomyia spencerella and O. phaseoli were distinct. However, overlap existed in male O. spencerella, O. phaseoli and C. horticola . In addition, there was overlap in female O. phaseoli, Tropicomyia vigneae and Liriomyza trifolii . The best discrimination in the male populations was obtained using the ratio of the proximal to the distal part of wing vein (M 3+4 ). In the female populations, the best discriminating character was hind tibia length.

Resistance in peas, Pisum Sativum L., Against pea leaf miner, Chromatomyia Horticola (goureau) (Diptera: Agromyzidae): biology, feeding and ovipositional preferences

Studies on developmental biology and feeding and ovipositional preferences of the pea leaf miner, Chromatomyia horticola (Goureau), were carried out on 11 varieties of field peas, Pisum sativum L. Two varieties, P-200 and P-402, offered maximum resistance to the development of pea leaf miner by inhibiting growth as both larval and puparial development were prolonged, and adult longevity, survival and fecundity reduced. These varieties were also least preferred for feeding and oviposition. Differences between the moderately resistant HFP-4 and highly susceptible varieties HFP-5, HFP-6, HFP-12, PG-3, RAU-21, RAU-25, RAU-37and T-163 were not well marked, as most of these had a relatively high value for the developmental success index, based on indices for larval-puparial development, adult longevity, survival and fecundity, and were also highly preferred by the ovipositing females. Variety PG-3, though offering some resistance to development, was highly preferred for oviposition. The local variety T-163, was the most susceptible variety, as it had the maximum value for the developmental success index, and was highly preferred by ovipositing females. The physiological basis of resistance in the two pea varieties is suggested to be mainly non-preference and antibiosis.

An integrated approach to the management of the major diseases and insect pests of peas in India

Abstract Prophylactic fungicidal seed treatment, foliar fungicidal sprays and insecticidal sprays were compared in different combinations against the major pea pest complex. The severity of powdery mildew (Erysiphe polygoni) rust (Uromyces vinciae‐fabae) and leaf blight (Ascochyta pisi) and damage caused by pod borer (Etiella zlnckenella) and leaf miner (Chromatomyia horticola) were recorded at their lowest level in treatments where fungicidal and insecticidal treatments were combined. The highest yield of 15.88 q/ha (quintals per hectare) was obtained when seeds were treated with carbendazim and thiram combined with two fungicidal foliar sprays each of mancozeb and dinocap followed by a single insecticidal spray of endosulfan. Results indicate that a combination of seed treatment, fungicidal sprays and insecticidal spray was more successful against the pea pest complex and increased yields compared to fungicides and insecticides used separately. Seed treatment alone did not reduce the severity of the dis...

Phytomyza atricornis . [Distribution map

Abstract A new distribution map is provided for Phytomyza atricornis [Chromatomyia horticola] Mg. (Dipt., Agromyzidae) (Chrysanthemum leaf-miner). Hosts: Wide range of herbaceous plants, notably bean, pea, brassicas, Chrysanthemum . Information is given on the geographical distribution in EUROPE, Austria, Belgium, Britain, Bulgaria, Czechoslovakia, Denmark, Faeroe Islands, Finland, France, Germany, Hungary, Iceland, Ireland, Italy, Netherlands, Norway, Poland, Spain, Sweden, Switzerland, Yugoslavia, ASIA, Afghanistan, China, Cyprus, Formosa, Hong Kong, India, Indonesia, Iran, Iraq, Israel, Japan, Korea, Pakistan, Thailand, Turkey, USSR, AFRICA, Azores, Cameroun, Canary Islands, Cape Verde Islands, Congo, Egypt, Eritrea, Kenya, Libya, Madeira, Morocco, Republic of South Africa, Rhodesia, Senegal, AUSTRALASIA and PACIFIC ISLANDS, Australia, New Zealand, NORTH AMERICA, Canada, U.S.A.