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KEYWORDS: arthropod biodiversity, community dynamics, abundance, organic rice ecosystems, biodiversidad de artrópodos, dinámica de la comunidad, abundancia, ecosistemas de arroz orgánico
The diversity and community structure of arthropods in an organic double-cropped rice ecosystem in Guangdong Province, China was studied. We compared the arthropod communities in the early season (Apr–Jul) crop to those in the late season (Aug–Nov) crop in 2009. The comparisons were undertaken using a combination of community assessment approaches, including morphospecies richness, the Shannon-Weaver diversity index, H', the Pielou-evenness index, J, the Simpson dominance index C, the Jaccard similarity index q and the compositions of the sub communities. We collected 114 species of arthropods, which consisted of including 58 species of spiders, 16 species of predatory insects, 25 species of phytophagous insects, 15 species of neutral/other insects, in early season crop. Subsequently we collected 109 species of arthropods, which consisted of 50 species of spiders, 19 species of predatory insects, 24 species of phytophagous insects, and 16 species of neutral/other insects, in the late season crop. There were no significant differences (P < 0.05) between the arthropod communities of the early and late season rice crops with respect to the Shannon-Weaver diversity index, the Pielou evenness index and the Simpson dominance index. Moreover the Jaccard similarity index in early and late season rice was as high, i.e., 0.70. The spider sub community had the greatest number of species in both rice crops, but the phytophagous insect sub community had the largest number of individuals in both rice crops. The dominance of predatory insects in the early season rice crop was significantly lower (P < 0.05) than in late season crop, but there was no significant difference in the composition of the neutral/other subcommunity between the early and late season rice crops.
Common salvinia, Salvinia minima Baker, is an aquatic invasive fern that obstructs waterways and impacts water quality throughout the southeastern United States. In an effort to establish populations for classical biological control of this weed, the weevil, Cyrtobagous salviniae Calder and Sands, was released at multiple sites across Louisiana. Many of the release sites were lost due to a variety of ecological and anthropological disturbances. In 2008, C. salviniae was found to have successfully overwintered on S. minima in Gramercy, Louisiana. Attack by Cyrtobagous salviniae significantly increased the number of damaged terminal buds and decreased the fresh weight biomass of S. minima.
Phenacoccus solenopsis, the cotton mealy bug, has emerged as a serious pest of cotton in India, necessitating basic studies on its development and survival at different temperatures (20, 25, 30 and 35 °C) and relative humidities (RH) (65, 75 and 85 ± 1 %) levels to ascertain optimal population growth. A life table was constructed using temperature and humidity. The nymphal duration was 20.2 d at 35 ± 1 °C and 65 ± 1% RH, but lengthened to 26.6 days at 20 ± 1 °C and both RH combinations. Adult longevity was 16.4 days at 20 ± 1° C and 65% RH, but 10.8 days at 35 °C at the same RH; however it was 6.4 days at a temperature of 20 ± 1 °C and 75% RH. Fecundity was at its maximum (489 nymphs/female) at 35 ± 1 °C and 65% RH, with lower fecundity at 75% RH across all temperature levels. The net reproductive rate (Ro) and finite rate of increase (λ) were 141.3 females/female/generation and 1.24 fold per female per day, respectively at 35 ± 1 °C and 65% RH suggesting that the population would increase more than 140 times per generation and 1.24 times per female per day. The rates of increase at higher relative humidities were generally lower than at 65% RH. Nymphs failed to complete development at 85% RH at all temperature levels. The intrinsic rate of increase (rm) was the highest (0.215) at 35 °C in combination with 65% RH. Our results suggest that 35 ± 1°C and 65% RH is the most favorable temperature and RH combination for the optimal population growth of the Punjab strain of P. solenopsis. Our study also predicts the expansion of this pest to other parts of the world in which the average temperature equals to 35 °C with 65% RH.
We describe Aeolothrips romanruizisp. nova that has been recently discovered in mango orchards in the Isthmus region of Oaxaca in southern Mexico. Aeolothrips romanruizisp. nova exhibits an ornamentation of the mesonotum and metanotum very different from others in this genus, except A. microstriatus, which is similarly ornamented; but these 2 species differ in forewing color pattern, body size and some other characters of chaetotaxy. A key to the Aeolothrips species of Central America and Mexico is provided.
Huanglongbing (HLB), the citrus disease associated with the bacteria ‘Candidatus Liberibacter asiaticus’, is the most important threat of the Mexican citrus industry. Since 2009, this bacterium has been detected in 11 out of 23 citrus producing states of the country, although with a limited distribution in each state. The Asian citrus psyllid (Diaphorina citri Kuwayama [Hemiptera: Psyllidae]) is the vector of this bacterium; the insect is distributed in all the citrus growing zones of Mexico. Presently, the lime production zone in the Mexican states of Colima, Jalisco, Michoacán, Nayarit, and Sinaloa, near to the Pacific Ocean coast, is the most affected by this disease. One of the main strategies to retard or stop the advance of HLB consists in the regional management of the psyllid populations. In order to contribute to the support of this strategy we analyzed the daily courses of temperature and rainfall all over the country to classify the citrus zones according to the probability of occurrence of favorable conditions for rapid and continuous psyllid reproduction. The results indicate that one of the most important regions of sweet orange production of Mexico, southern Veracruz and the region named “La Huasteca”, where the states of Veracruz, Tamaulipas, San Luis Potosi and Hidalgo converge, represent the zones with the highest risk for an accelerated reproduction of the psyllid. At present these regions remain free of the bacterium and are considered of highest priority for the management of psyllid populations and for preventing the entry and establishment of HLB.
Silicon (Si) is the second most abundant element in soils, and at elevated concentration levels in plant tissue Si is reported to improve plant resistance to a range of biotic and abiotic stresses. In the present study, Si solutions at 100, 300 or 500 mg L-1 made from potassium silicate (K2SiO3) were applied as foliar sprays or soil drenches to pepper (Capsicum annum L.) plants, and their effects on chilli thrips (Scirtothrips dorsalis Hood) populations were studied. Data from 3 greenhouse tests showed minimal effects of Si treatments on visual leaf damage and numbers of thrips recovered from infested plants. An addition of jasmonic acid (a plant defense elicitor) with or without Si applications also did not alter the proportion of pepper leaves that sustained thrips damage. Tissue analyses showed that soil-drenched plants were able to absorb Si in roots up to ≈2.5% (w/w), but the Si was not being translocated to leaf or stem tissues at an equivalent rate. Foliar application of Si resulted in close to 0.5% (w/w) of Si in leaf tissues. Plant biomass was not affected by Si applications. We conclude that pepper plants treated with potassium silicate solutions did not accumulate to sufficient Si levels in leaf tissues to protect against thrips feeding or reproduction. To our knowledge this is the first study of Si application to pepper plants for attempts to control an insect pest.
Leucothyreus femoratus Burmeister (Coleoptera: Scarabaeidae) is an important insect pest of oil palm plantations, because larvae and adults feed on plant roots and leaves, respectively. This suggests the necessity of comprehending the pest's feeding and behavioral habits for pest management. Food consumption and injury to leaves of Elaeis guineensis Jacq. (Arecales: Arecaceae, African oil palm) by adults of L. femoratus in Colombia were studied. Locomotion of adults was evaluated with respect to 6 behaviors, i.e., emergence, hiding in the ground, walking, flying, feeding, and mating. In addition, larvae were collected from the roots of other plants found in the oil palm plantation in order to determine possible alternative hosts. Leaf consumption per adult L. femoratus was 13 mm2/day/insect (χ2 = 19.33, P < 0.0001). Leaf injury was in the form of squares or rectangles and cumulative defoliation reached 15.5% in 60 days. The insect showed predominantly nocturnal feeding and mating (χ2 = 95.53, P < 0.05; χ2 = 207.01, P < 0.05, respectively). Larvae of L. femoratus were found in abundance on the roots of Croton trinitatis Millsp. (Euphorbiaceae, road side croton) and Imperata cilindrica (L.) P. Beauv. (Poaceae, cogon grass). The feeding habits of larvae and adults of this insect may be main factors in their adaptation to oil palm plantations. The understanding of the feeding habits and behaviors of L. femoratus are important to define strategies for the management of their populations in oil palm plantations.
The new species, Casminola subseminigra sp. nov. (Lepidoptera, Noctuidae, Nolinae), is described from China. It is similar to C. seminigra (Hampson, 1896), but can easily be distinguished from it by the forewing lacking an antemedial line; the male genitalia with an uncus broad medially with a curved and pointed apex; and the signa being absent in the female genitalia. Illustrations of adults and genitalia are provided.
Albizia julibrissin Durazz and Cercis siliquastrum L. (Fabales: Fabaceae) are native to Turkey and used as ornamentals. We studied the seed beetles Bruchidius terrenus (Sharp) and B. siliquastri Delobel (Coleoptera: Chrysomelidae: Bruchinae), which infest the seeds of A. julibrissin and C. siliquastrum, respectively, and their parasitoids. We recorded both bruchines from Turkey for the first time. We also found Dinarmus acutus (Hymenoptera: Pteromalidae) as a parasitoid of both B. terrenus and B. siliquastri.
The effects of 2 varieties of tomato, Solanum lycopersicum L., i.e., ‘Charanda F1’ and ‘Rafaello’, were evaluated on the morphometries of Bactericera cockerelli (Sulc). Eggs, nymphs, and adults of B. cockerelli were collected from 2 varieties of tomato, ‘Charanda F1’ and ‘Rafaello’, under greenhouse conditions in the Colegio de Postgraduados, Campus Montecillo, Texcoco, the State of Mexico, during the periods Oct-Dec 2009 and Jan-Mar 2010. Since 2000–2001 the B. cockerelli cultures were maintained on tomato with no exposure to agro-chemicals. Adult B. cockerelli were kept in individual growth chambers constructed of wooden frames covered with organza cloth, under 14:10 h L:D and temperatures ranging from 10 to 25 °C. For morphometric analysis of the eggs, the following variables were investigated: egg length (LH), egg width (AH), and pedicel length (PED). For nymphs, the variables were: body length (LC), body width (AC), and antennal length (ANT). For adults, the variables were: body length (LC), body width at thorax (ACT), wing length (LALA), and wing width (ANALA). The 2 tomato varieties were found to have differential morphometric effects on B. cockerelli as follows: no significant differences on egg length (F1,41 = 0.57; P = 0.4551), but egg width was differentially affected by the variety of tomato (F1,41 = 11.92; P = 0.0013). There were significant differential effects of tomato variety on nymphs: body length (F4,324 = 1199.2; P < 0.0001), body width (F4,324 = 900.72; P = 0.0001); and antennae length (F4,324 = 883.93; P = 0.0001). Body length of the adults (F1,117 = 7.11; P = 0.0087) was differentially affected by the 2 different tomato varieties. None of the plants showed any symptoms of infection by ‘Candidatus Liberibacter solanacearum’, which is known to cause effects on B. cockerelli fitness traits. Body width and antennal length of nymphs can be recommended to differentiate all 5 nymphal instars on this pest species, which has practical implications.
We evaluated 3 species of predacious mites (Acari: Phytoseiidae), Galendromus occidentalis (Nesbitt), Phytoseiulus persimilis Athias-Henriot and Neoseiulus californiens (McGregor), as biological control agents for citrus red mite, Panonychus citri (McGregor) (Trombidiformes: Tetranychidae), on citrus in southern Alabama. Three separate experiments were carried out during 2008 and 2011 to evaluate various factors (i.e. release rate, release frequency and initial prey density) that may impact the performance of the predacious mites. In the first experiment conducted in 2008 on trees with moderate initial prey densities (i.e. < 4 P. citri motiles per leaf), one single release of P. persimilis or G. occidentalis at a rate of 100 or 200 per tree effectively prevented the prey from exceeding the economic threshold (5 motiles/leaf) for the entire duration (35 d) of the experiment. The result of the second experiment in 2008 on trees with high initial prey densities (i.e. ≥ 5 motiles per leaf) showed that 2 releases of P. persimilis or G. occidentalis at a rate of 100 or 200 per tree per release could not provide adequate suppression of P. citri below the economic threshold. In both experiments, P. citri densities were significantly lower in most predacious mite treatments compared to the control (no release). Also, lower P. citri densities were recorded at the higher release rate (200 per tree) compared to the lower rate, but this was only significant in a few cases. The third experiment conducted in 2011 in large plots on trees with low initial P. citri densities (i.e. < 1 motile per leaf) showed that 2 releases of N. californiens or P. persimilis at a rate of 200 per tree per release effectively maintained P. citri at low densities (< 1.5 motiles per leaf) throughout the duration (56 d) of the experiment. Limited observations in spring 2012 confirmed the establishment of the predacious mites released in the 2011 study. These results showed that all 3 phytoseiid species were effective in reducing P. citri densities on citrus. However, initial prey density may be an important factor influencing their performance.
Intercropping fennel (Foeniculum vulgare Mill.) with naturally colored cotton (Gossypium hirsutum L.) may provide a beneficial socioeconomic, ecological and environmental alternative for recuperating agribusiness in fennel and cotton cultivations in northeast Brazil because these crops do not compete for nutrients. The objectives of this study were to investigate the vertical and horizontal distribution of Hyadaphis foeniculi (Pass.) within fennel plants and its population dynamics in fennel crops and fennel intercropped with naturally colored cotton as a function of plant age during 2 fennel seasons by examining plants throughout the entire growing seasons. The vertical and horizontal distributions and the dynamics of the fennel aphids on the monocultured fennel and fennel intercropped with cotton were determined at intervals of 7 days, sampling 5 whole plants per plot from 55 days after transplanting the fennel seedlings until the first harvest (195 days after transplanting). The vertical distribution of apterous or alate aphids on the fennel plants evidenced no significant interactions within the cropping system, plant age, or vertical region of the plant, or between the cropping system and the vertical region of the plant. However for the number of fennel aphids per plant, there was an interaction between cropping system and plant age (apterous aphids) and between plant age and vertical region of the plant (apterous or alate aphids). In the fennel system, the apterous aphid population peaked at 153 and 188 days after transplanting, whereas the alate aphid population peaked at 139 and 174 days after transplanting. In the intercropped fennel/cotton system, the apterous aphid population peaked at 188 days after transplanting, and the alate aphid population peaked at 195 days after transplanting. The numbers of apterous aphids found per fennel plant in the monocultured fennel for the entire study were significantly higher than the numbers found in the fennel-cotton intercropped system. The results of our study are extremely important for understanding the vertical and horizontal distribution of H. foeniculi on fennel plants in both monoculture and the fennel-cotton intercropping system and may be useful in decision-making in relation to implementing controls and determining the timing of population peaks of this important fennel pest.
The Asian citrus psyllid (ACP), the principal vector of the pathogen of huanglongbing (HLB), has been reported to be transported in truckloads of oranges in Florida. Citrus, especially Key limes and lemons, are shipped to the U.S. from Mexican states that are heavily infected with HLB. Live, infected psyllids could spread the disease in orchards near inspection facilities or packing houses where trucks are unloaded. Experiments reported here tested the use of a sticky trap with light emitting diode(s) (LED) to detect possible contamination of fruit loads by ACP in containers. Experiments were performed in chambers maintained at temperatures and humidities similar to those in truck trailers arriving from Mexico. The effects of light intensity (no LED, 1 LED, 2 LEDs) and plant material (no material, fruit only, trees and fruit) were measured and analyzed to determine the relative efficacy of the trap types and to the role of plant material in a system to detect the ACP Results showed that ACP could survive in containers with no plant material, fruit only, or a nursery tree as material. The majority of the insects were recovered from the traps with lower psyllid numbers surviving or dying in the container. The traps with 2 LEDs were the most effective, followed by 1 LED traps, then those with no lights. These results showed that the psyllids in these chambers were more likely to be trapped than to survive or die in the chamber. Thus, sticky traps with LEDs as a light attractant can be effective means to detect psyllid contamination in citrus shipping.
We conducted a survey of insects and pest management practices on 40 farms growing Heliconia spp. and other Zingiberales in the central coffee region of Colombia in 2006 and 2007. Most farmers (87%) were concerned about insect pests in the plantation and 90% used broad-spectrum insecticides (chlorpyrifos, carbofuran, acephate and malathion) at least monthly. Fewer (approximately one third) used biological or cultural control practices. In total insects from 13 orders and 99 families were collected from Heliconia farms. The most abundant orders were Diptera (23 families), Hemiptera (22 families), Hymenoptera (14 families), Coleoptera (13 families), and Lepidoptera (7 families). The most common phytophagous species were hispine beetles (Chrysomelidae), scales (Coccidae: Ceroplastes sp., Saissetia sp.), leafhoppers (Cicadellidae), stinkbugs (Pentatomidae), squash bugs (Coreidae) and leaf cutting ants (Atta and Acromyrmex spp.). Other insects such as Metamasius and Pandeleteius weevils were found on the rhizome or pseudostem. Beneficial insects collected included several predatory families (Coccinelidae, Chrysopidae and Reduviidae) but only low numbers of parasitoids (Ichneumonidae, Braconidae, Chalcididae and Stephanidae). A range of insects occurred in empty and water-filled bracts of inflorescences notably flower feeding or detritivorous Diptera (Chironomidae, Drosophilidae, Richardiidae, Syrphidae, Tephritidae and Ulidiidae). Our survey suggests many new insect host associations for Heliconia. The use of broad-spectrum insecticides may not be the best long term strategy for insect pest management in Heliconia due to adverse risks to human and environmental health.
A field experiment was conducted from Oct to Dec in the 2009 and 2010 planting seasons at the Vegetable Evaluation and Research Sub-Station farm located at Praslin, Seychelles to evaluate the effectiveness of 3 insecticides namely lambda-cyhalothrin, deltamethrin and mercaptothion, to control the melon fruit fly (Bactrocera Cucurbitae) in the cucumber crop. The 3 insecticides constituted the treatments, replicated 4 times in a randomized complete block design. The results obtained showed that the use of deltamethrin insecticide recorded the lowest number of ovipositor marks, number of pupae and number of emerged melon fruit flies. The number of melon fruit flies that emerged with the use of deltamethrin insecticide was significantly (P ≤ 0.05) decreased by 19.0% and 38.1%, respectively, in 2009 and by 10.0% and 44.4%, respectively, in 2010 compared to that recorded with the use of lambda-cyhalothrin and mercaptothion. The highest number of marketable cucumbers was produced from plots sprayed with deltamethrin; and which was significantly (P ≤ 0.05) increased by 50.5% and 62.9%, respectively, in 2009 and by 29.0% and 50.7%, respectively, in 2010 compared to those obtained when lambda-cyhalothrin and mercaptothion were used. This study showed that deltamethrin insecticide was the most effective, and could be recommended for the control of melon fruit fly in cucumber under field conditions.
Megamelus scutellaris Berg (Hemiptera: Delphacidae) is a South American species that feeds on waterhyacinth, Eichhornia crassipes Mart. (Solms). This species exhibits significant wing dimorphism whereby fully winged adults (macropters) are capable of flight while those with reduced wings (brachtypters) are not. The wing form is determined by a developmental switch triggered by environmental factors including crowding, host plant quality, temperature, and photoperiod. This study examined the influences of insect density and host plant quality on M. scutellaris wing dimorphism, development, and biomass as well as their effects on E. crassipes. Two experiments exposed a single generation of M. scutellaris to lower and higher densities of conspecifics on low and high quality plants. The first experiment involved transferring second instars to test plants at loads of 50, 5, or 1 g of fresh weight plant biomass per nymph, which resulted in mean densities of 2, 15, and 69 nymphs, respectively, on both low and high quality plants. A second experiment exposed test plants to 2, 4, or 20 M. scutellaris adults for 7 days and allowed their progeny to develop into adults which ultimately produced densities of 0, 56, and 352 F1 adults, respectively, per low and high quality plants. No macropterous adults were produced in any treatment combination in either experiment. Several plant variables were affected by insect densities and plant quality including the mean relative growth rate, the change in leaf number, and the percentage of dead leaves on a plant. Megamelus scutellaris appeared to have a relatively high density threshold for macroptery within the range of host quality used in these studies. This may promote more brachyptery which, in turn, may increase the chances of this insect reaching damaging densities in field populations of E. crassipes.
Bed bugs were common pests worldwide before World War II. They were almost completely eradicated in many countries by good hygienic conditions and application of insecticides. These pests are currently reemerging in many developed countries. We conducted a literature review and an internet search using the key word, bed bugs, to evaluate the status of bed bug resurgence in China. The results showed that the occurrence of bed bugs dramatically increased from 4 reports in 2007 to 67 in 2012. Bed bug infestations were reported from 23 provinces of China, with the most severe infestations occurring in Guangdong Province. Bed bugs were reported to commonly invade dormitories, private homes, rented houses, and public transportation facilities. Based on internet reports, about half of the people bitten by bed bugs claimed to have developed clinical reactions, and approximately 5% required medical treatment. This study demonstrates that China also has undergone a bed bug resurgence, which should be addressed by the multidisciplinary actions involving both governments and the public.
Brazilian peppertree, Schinus terebinthifolia Raddi (Anacardiaceae), a perennial woody plant native to Brazil, Argentina, Uruguay and Paraguay, has become one of the most invasive weeds in Florida. A leaflet pit galling psyllid, Calophya terebinthifolii Burckhardt & Basset (Hemiptera: Calophyidae), has been identified as a potential biological control agent for Brazilian peppertree. However, biological information on the psyllid, including its life history, rearing procedures and potential distribution, is lacking. This type of information is essential when importing an insect for biological control purposes. From May–Aug 2009, field and laboratory research was conducted in Gaspar, Santa Catarina, Brazil with psyllids collected from the Atlantic coastal region of Santa Catarina. Laboratory studies on the psyllid in Brazil focused on: female fecundity (55.3 ± 8.9 eggs/female), the number and size of the immature stages, age-specific survivorship, and mean generation time (43.7 ± 1.2 days). Preliminary evidence from feeding trials suggests this psyllid from the Atlantic coastal region of Santa Catarina is locally adapted to Brazilian peppertree plants of haplotype A, which is one of the genetic types that invaded Florida. Ecological niche modelling with MaxEnt confirmed there was climatic overlap between Florida and the native range of the psyllid in South America. Using collection and survey locations of the psyllid in its native range and point locations for haplotype A plants in Florida, a map was created that predicted Volusia, coastal Pasco and Hernando counties, and a small section of southwestern Polk county as suitable locations for establishment of the psyllid if it is approved for release as a biocontrol agent.
A new species of springtail (Symphypleona, Collophoridae), Collophora brasilissp. nov., is described, the first species known from Brazil. The species is distributed from the coastal region to the semi-arid region in northeastern Brazil. It is characterized by the reduction in the trochanteral setae and teeth on the empodial complex. Diagnostic features are illustrated and compared to other members of the genus.
KEYWORDS: temperature requirements, biological control, Diatraea saccharalis, parasitoid, sugarcane production, Trichospilus diatraeae, requerimientos de temperatura, Control biológico, parasitoide, producción de caña de azúcar
Knowledge of the thermal requirements of Trichospilus diatraeae (Hymenoptera: Eulophidae) is important if it is to be used successfully in to control Diatraea saccharalis (Lepidoptera: Crambidae) in sugarcane plantations. In the current study, the development of T. diatraeae was investigated in the pupae of D. saccharalis incubated at different temperatures. Seven T. diatraeae females were placed with host pupae for 24 h in tubes within chambers at 16, 19, 22, 25, 28 and 31 °C with 70 ± 10% RH and 14:10 h L:D. The life cycle duration of T. diatraeae decreased as the temperature increased, although no development was recorded at 31 °C. The number of T. diatraeae progeny per female ranged from 264.8 ± 40.7 (at 16 °C) to 385.1 ± 36.3 (at 25 °C), but no significant difference were recorded among temperature treatments (P > 0.05). The base temperature (Tb) and thermal constant (K) of T. diatraeae were 9.37 °C and 257.60 degree-days, respectively. The estimated average numbers of generations per year of T. diatraeae in pupae of D. saccharalis were 18.5, 19.93 and 17.73 for Dourados, Ivinhema and Ponta Porã municipalities of Mato Grosso do Sul State, Brasil, respectively.
The whitefly Bemisia tabaci (Gennadius), a major pest of protected and outdoor crops worldwide, has developed resistance to a wide range of insecticides including organophosphates (OPs) and carbamates (CBs). The biochemical target of OPs and CBs is acetylcholinesterase (AChE). The objective of this study was to optimize AChE bioassay conditions including enzyme concentration, substrate concentration, pH, temperature and reaction time in order to quickly and accurately monitor specific activity of AChE and monitor resistance of B. tabaci to insecticides. The results of an orthogonal array test showed that the optimum combination of levels was A3B3C4D5E1 in which the enzyme concentration was 20 adults/mL, substrate concentration was 7.0 × 10-4 mol/L, pH was 7.5, temperature was 45 °C, and reaction time was 5 min. The specific activity of AChE from B Biotype B. tabaci was 41.23 nmol ·min-1 · mg-1 under this set of conditions. This optimum combination proved to be reliable and accurate for testing the specific activity of AChE.
We conducted field surveys of the emerald ash borer (EAB), Agrilus planipennis Fairmaire, and associated larval parasitoids in western and central Pennsylvania (Cranberry Township in Butler County and Granville in Mifflin County) in the spring and fall of 2009. The survey procedure involved destructively debarking sections of the main trunk (bole) of EAB-infested green ash (Fraxinus pennsylvanica Marsh.) trees from the ground to the height of 2 m. Three species of the hymenopteran parasitoids were consistently recovered from EAB larvae observed in both survey sites, including two indigenous species of braconids, Spathius laflammei Provancher (= Spathius benefactor Matthews) and Atanycolus nigropyga Shenefelt and the exotic (accidentally introduced) eupelmid Balcha indica (Mani & Kaul). In addition, there are three unidentified species of hymenopteran parasitoids including two braconids Atanycolus sp. [possibly Atanycolus disputabilis (Cresson)] and Spathius sp. (at the Butler Co. site) and one ichneumonid Dolichomitus sp. (at the Mifflin Co. site). These parasitoids together parasitized 0.5–4.6% and 0.5–1.5% of the sampled EAB hosts at the Butler and Mifflin Co. sites, respectively. Parasitism rate by each species or group of those hymenopteran parasitoids varied between the two survey sites—with parasitism rates being generally higher at the Butler Co. site than at the Mifflin Co. site. Studies are needed to determine if those new associations of North American indigenous braconid parasitoids with EAB may play a complementary role in controlling this invasive pest.
The purpose of this work was to study the population dynamics of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) in orchards of ‘Valencia’ orange, ‘Ponkan’ mandarin, and ‘Murcott’ tangor trees located at the São José farm in the municipality of Taquaritinga, São Paulo (SP). Yellow sticky traps used to monitor this disease vector were evaluated monthly for 4 yr between Sep 2004 and Aug 2008. The largest number of D. citri was captured on the ‘Ponkan’ mandarin trees followed by the ‘Murcott’ tangor and ‘Valencia’ orange trees with significant differences. Chemical pest control and environmental factors likely are responsible for these results. Pearson's correlation analysis indicated that there is a weak correlation between the abundance of D. citri and the environmental factors of temperature and precipitation. An analysis of variance suggested that there was a significant difference in the abundance of D. citri among the 3 citrus tree varieties, and the autocorrelation was significant for the ‘Valencia’ orange orchard. Spectral analysis indicated that there were greater frequencies of peaks in the ‘Ponkan’ mandarin and ‘Murcott’ tangor trees, and the simulations performed using a stochastic logistic model suggested that the psyllid populations on orange trees are the most susceptible to local extinction; this result likely occurred because of the high levels of chemical control applied to orange trees. Therefore, in a D. citri management program, the different citrus varieties planted on a farm should be considered, thus varieties without the proper management of the vector does not become a source of psyllids for infestation of other varieties.
The semi-aquatic weevil Bagous hydrillae was released during 1991–1996 at 19 sites in 4 states in attempts to control the aquatic weed hydrilla, Hydrilla verticillata. Fourteen of the sites were in Florida, 2 each in Texas and Georgia and one site in Alabama. Over 320,000 adult weevils were included in these releases. Despite the fact that a few adults were recovered as late as 4.5 yr post-release, presence of permanent, self-perpetuating populations was never confirmed. Then, during 2009 adult B. hydrillae were collected in southern Louisiana, at least 580 km from the nearest release site and 13 yr after attempts to establish this insect had terminated. This suggests that earlier recoveries were indicative of successful establishment and that this weevil species has persisted and dispersed widely in the southeastern USA. Nonetheless, there is no evidence that B. hydrillae has had a suppressive effect on hydrilla.
Huanglongbing (HLB), considered one of the most lethal diseases of citrus worldwide, has reached the main areas of Mexican lime (Citrus latifolia Tanaka) fruit production on the Pacific coast of México. Growers have initiated intensive use of insecticides in order to control populations of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), the vector of the pathogen, ‘Candidatus Liberibacter asiaticus’ associated with huanglongbing. Presently, costs of insecticides and the side effects of their use are major concerns, because they could impair the management strategy against the vector; and thus, ecologically and economically viable alternatives to conventional insecticides are required in the short term. Therefore the goal of this study was to evaluate the pathogenicity of 27 native isolates and 3 strains of entomopathogenic fungi and determine their potential as biological control agents of D. citri by using 2 different bioassay methods. Bioassays were performed under laboratory conditions (26 ±2 °C, 60 ±5% RH and 16:8 h L:D) by exposing adult insects to a concentration of 1 × 108 conidia per milliliter using 2 different application methods, i.e., spraying the spores onto the citrus seedlings and spraying the spores directly onto the adult psyllids. The results showed that by direct spraying the adults, HIB-24 (B. bassiana) and HIB-32 (I. fumosorosea) isolates showed the highest mortality (60.66%). Regarding spraying of the seedlings, HIB-19 (I. fumosorosea) showed the highest percentage of mortality (62.02%). The results from this study demonstrate potential for using entomopathogenic fungi in the management of D. citri in México.
In this paper a new parasitoid Megastigmus Dalman, 1820 (Hymenoptera: Chalcidoidea: Torymidae: Megastigminae) species was described in the subgenus Torymus, associated with the gall-forming Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae) in eucalypt plantations in Brazil.
The yellow-necked drywood termite, Kalotermes flavicollis (F.), so called due to the yellow pronotum of its alates, is the only species in the genus Kalotermes known for Europe. In some Italian localities, K. flavicollis swarms can contain a small proportion of alates with a dark pronotum, but otherwise not different from the normally colored K. flavicollis. This color variation was described by G. Becker in 1955 as Kalotermes flavicollis var. fuscicollis. During collecting trips in central Italy, we found in Grosseto Marina (Tuscany) a Kalotermes population whose alates all have a very dark pronotum. Compared with K. flavicollis alates, Grosseto alates also have paler wings and smaller arolia. Grosseto soldiers have eyes smaller than those of K. flavicollis soldiers. Kalotermes sp. form Grosseto also differs morphologically from the other Kalotermes species known for the circum-Mediterranean lands. The population from Grosseto has mitochondrial DNA sequences (a partial sequence of the control region and a fragment including a portion of COI, tRNA-Leu and a portion of COII) quite different from K flavicollis (p-distance: 5.6–7.3%). Some Kalotermes populations from Tuscany and Marche, morphologically classifiable as K flavicollis, have sequences similar to those of Grosseto Kalotermes (p-distance: 0.1–1.0%). These populations are possibly hybrids between K. flavicollis and Kalotermes sp. from Grosseto. Because of its morphologic and genetic distinctive features, we describe Kalotermes sp. from Grosseto as Kalotermes italicus sp. nov.
The encyrtid wasp, Psyllaphycus diaphorinae Hayat, was reared from nymphs of Asian citrus psyllid, Diaphorina citri Kuwayama, on Citrus spp. and Murraya sp. collected in Faisalabad, Punjab, Pakistan. This discovery is a new host record for P. diaphorinae, which previously had been known only from India from a different, congeneric host. Taxonomic notes on this little known species are given, illustrations of both sexes are provided, and its potential as a prospective classical biological control agent against D. citri is discussed. A correction to the diagnosis of the genus Psyllaphycus Hayat is made: both sexes have the mandible with 2 teeth and a wide truncation.
Hannara Park gen. nov., related to CrocanthesMeyrick, 1886 (Gelechioidea, Lecithoceridae), is described from New Guinea, based on the type species, Hannara buloloensis Park sp. nov. and H. gentis Park sp. nov. Illustrations of adults, labial palpi, and genitalia for the described species are provided.
KEYWORDS: Acrididae, floriculture, population, fluctuation, herbivores, Romaleidae, Para State, Estado do Pará, floricutura, Herbívoros, flutação populacional
Despite the expansion of floriculture, little is known about insects associated to this crop in northern Brazil. The objective was to identify the main species of defoliator grasshoppers, associated to crops of Heliconia spp. in the northeastern region of State of Pará, Brazil , in the municipalities of Castanhal, Belém and Benevides, from Aug 2004 to Mar 2005. Representatives with higher abundances in these municipalities were the orders Coleoptera, Thysanoptera, Hemiptera and Orthoptera. The collected species of Orthoptera were Cornops frenatum frenatum (Marshall) and Eutropidacris cristata L. (Orthoptera: Acrididae), Prionolopha serrata L. and Chromacris speciosa Thunberg (Orthoptera: Romaleidae), which present a substantial potential to damage heliconias crop in northeastern Pará, Brazil.
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