Ursinia nana (Anthemideae, Asteraceae), and adventive from South Africa which is becoming naturalized in the Iberian Peninsula. Observations about its reproductive biology and fruit dispersal mechanism.

The presence of Ursinia nana, an Anthemideae of South-African origin which has been introduced into the NE Iberian Peninsula, is reported for the fi rst time in Europe. The data offered cover its precise location, morphology, chromosome number, ecology and a population census, as well as its life cycle, fl oral structure, reproductive biology and fruit dispersal mechanisms. Of special note are the clear predominance of autogamy (geitonogamy) over xenogamy as a reproductive system and the large number of fruits produced with high and immediate germinative capacity. These characteristics permit rapid colonization by the introduced species, which can become invasive. However, fruit predation by the ant Messor barbarus points to a natural mechanism that helps regulate population growth and makes biological control possible. Finally its possibilities of expansion in the colonized area and of naturalization in the NE Iberian Peninsula are assessed.

Fusarium oxysporum strains as biocontrol agents against Fusarium wilt: effects on soil microbial biomass and activity

Before planning the large-scale use of nonpathogenic strains of Fusarium oxysporum as biocontrol agents of Fusarium wilt, their behaviour and potential impact on soil ecosystems should be carefully studied as part of risk assessment. The aim of this work was to evaluate the effects of antagonistic F. oxysporum strains, genetically manipulated (T26/6) or not (233/1), on soil microbial biomass and activity. The effects were evaluated, in North-western Italy, in two soils from different sites at Albenga, one natural and the other previously solarized, and in a third soil obtained from a 10-year-old poplar stand (Popolus sp.), near Carignano. There were no detectable effects on ATP, fluorescein diacetate hydrolysis, and biomass P that could be attributed to the introduction of the antagonists. A transient increase of carbon dioxide evolution and biomass C was observed in response to the added inoculum. Although the results showed only some transient alterations, further studies are required to evaluate effects on specific microorganism populations.

Reproductive characteristics of the predator Podisus nigrispinus fed with an insect resistant soybean variety

The objective of this research was to evaluate the effect of the insect resistant soybean genotype IAC 17 on reproductive characteristics of Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) females compared to the soybean insect susceptible genotype UFV 16. Treatments were: T1) females of P. nigrispinus fed on plants of the UFV 16 and Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) caterpillars reared on leaves of this variety; T2) females of P. nigrispinus fed on plants of the IAC 17 and A. gemmatalis caterpillars reared on leaves of this variety. Longevity of females, pre-oviposition, oviposition and pos-oviposition periods, number of eggs and egg masses/female, egg weight, interval between egg mass laying, number of eggs/egg mass, percentage of nymphs, number of nymphs/female and total number of prey killed/female of P. nigrispinus were evaluated. Most of the characteristics evaluated showed similar results between treatments, but the oviposition period was longer for females reared on the resistant genotype than on the susceptible one and the percentage of total females that laid eggs was lower on the IAC 17. Also, the resistant genotype caused higher mortality of P. nigrispinus females at the beginning of its adult stage and egg production by females of this predator was better spread along its adult stage with this resistant genotype. On the other hand, results suggest no effect of the resistant genotype on the offspring of this predator.

Effect of two dosages of Metarhizium anisopliae var. acridum against Rhammatocerus schistocercoides Rehn

The fungus Metarhizium anisopliae var. acridum, strain CG 423, was tested under field conditions against the gregarious grasshopper Rhammatocerus schistocercoides (Rehn) (Orthoptera: Acrididae). Conidia formulated in a racemic mixture of soybean oil and kerosene were sprayed under field conditions using an ultralow-volume hand-held atomizer Ulva Plus adjusted to deliver 2.9 L/ha. Bands composed of 2nd instar nymphs were treated with either 5.0x10(12) or 1.0x10(13) viable conidia/ha. The number of insects in each band was estimated at day one following spraying and by the end of the field trial (15 to 16 days post-treatment). Reductions in population size reached, in average, 65.8% and 80.4% for bands treated with the higher and lower dosage, respectively. For both dosages, total mortality rates of insects collected at two days post-application, and kept in cages for 14 days under lab conditions, showed no significant differences as compared to that obtained with insects collected immediately after spraying. Healthy insects were fed to native grasses sprayed on the field with 1.0x10(13) viable conidia/ha. Mortality levels of the nymphs fed on grasses collected two and four days post-application were not affected when compared to nymphs fed on grasses collected immediately following application.

Inter and intra-guild interactions in egg parasitoid species of the soybean stink bug complex

The objective of this research was to evaluate the parasitism behavior of Telenomus podisi Ashmead, Trissolcus basalis (Wollaston) e Trissolcus urichi Crawford (Hymenoptera: Scelionidae) on eggs of Nezara viridula L., Euschistus heros F., Piezodorus guildinii Westwood and Acrosternum aseadum Rolston (Heteroptera: Pentatomidae), in no choice and multiple choice experiments. For all parasitoid species, the results demonstrated the existence of a main host species that maximizes the reproductive success. The competitive interactions among the parasitoid species were investigated in experiments of sequential and simultaneous release of different combinations of parasitoid pairs on the hosts N. viridula, E. heros and A. aseadum. Exploitative competition was observed for egg batches at the genus level (Telenomus vs. Trissolcus) and interference competition at the species level (T. basalis vs. T. urichi). Trissolcus urichi was the most aggressive species, interfering with the parasitism of T. basalis. Generally, T. basalis showed an opportunistic behavior trying to parasitise eggs after T. urichi had abandoned the egg batch. The selection of parasitoid species for use in augmentative biological control programs should take into account the diversity of pentatomids present in soybean in addition to the interactions among the different species of parasitoids.

Full-genome sequence of the plant growth-promoting bacterium Pseudomonas protegens CHA0.

We report the complete genome sequence of the free-living bacterium Pseudomonas protegens (formerly Pseudomonas fluorescens) CHA0, a model organism used in plant-microbe interactions, biological control of phytopathogens, and bacterial genetics.

Fertility life table of Trichogramma pretiosum and Trichogramma acacioi on eggs of Anagasta kuehniella at different temperatures

Species of the Trichogramma genus are among the most important ones for biological control. The objective of this research was to evaluate parasitism potential of two species of Trichogramma on eggs of Anagasta kuheniella through life fertility table, at temperatures between 15ºC and 35ºC. These species were collected in the State of Espírito Santo parasitising eggs of the avocado defoliator Nipteria panacea. Trichogramma pretiosum and T. acacioi showed adequate reproductive potential between 15ºC and 35ºC which indicates possibilities of using them in biological control programs in avocado plantations.

Survival in soil and detection of co-transformed Trichoderma harzianum by nested PCR

The objective of this work was to evaluate the survival of two Trichoderma harzianum co-transformants, TE 10 and TE 41, carrying genes for green fluorescent protein (egfp) and for resistance to benomyl, during four weeks in a contained soil microcosm. Selective culture media were used to detect viable fungal material, whose identity was confirmed by the observation of the fluorescent phenotype by direct epifluorence microscopy. PCR using two nested primer pairs specific to the egfp gene was also used to detect the transformed fungi. Although it was not possible to reliably detect the egfp gene directly from soil extracts, an enrichment step involving selective culture of soil samples in liquid medium prior to DNA extraction enabled the consistent detection of the T. harzianum co-transformants by nested PCR for the duration of the incubation period.

Pachycondyla obscuricornis as natural enemy of the spittlebug Deois flavopicta

The objective of this work was to evaluate the potential control of the ant Pachycondyla obscuricornis Emery (Hymenoptera Formicidae) on populations of nymphs of the spittlebug, Deois flavopicta Stal (Hemiptera Cercopidae). Foraging behavior and prey consumption rate of P. obscuricornis were evaluated. Field data revealed that P. obscuricornis does not show aggressive behavior against individuals of the same species, when they are not carrying a prey; they can patrol distances larger than 10 m searching for prey, and they can build their nest as close as 1 m from each other. The ant has a solitary patrolling habit, there is no recruitment behavior, and individuals dislocate fast, browsing on soil and vegetation for prey. Predation rate on spittlebug nymphs increased relative to the spittlebug abundance, reaching 93.8% of captured prey. Pachycondyla obscuricornis is a voracious predator and may control the population of spittlebugs in cultivated pastures.

Emergence, longevity and fecundity of Trissolcus basalis and Telenomus podisi after cold storage in the pupal stage

Pupae of Trissolcus basalis (Wollaston) and Telenomus podisi Ashmead (Hymenoptera: Scelionidae) were stored at 12ºC and 15ºC for 120-210 days, after different periods of parasitism at 18ºC in order to evaluate adult emergence, longevity and ovipositional capacity. There was no emergence of adults at 12ºC. The rate of emergence of parasitoids transferred to 15ºC at the beginning of the pupal stage was 1.5% and 26.3%, for T. basalis and T. podisi respectively, whereas those parasitoids transferred one day before the expected date of emergence at 18ºC showed 86.4% of emergence for T. basalis and 59.9% for T. podisi. Mean adult longevity was also significantly lower when pupae were transferred to 15ºC at the beginning of the pupal stage. Females emerged after storage and maintained for 120 to 210 days at 15ºC parasitized host eggs after transference to 25ºC; however, fecundity of T. podisi was reduced in about 80% after cold storage.

Parasitism by Campoletis flavicincta on Spodoptera frugiperda in corn

Parasitism by Campoletis flavicincta (Ashmead) (Hymenoptera: Ichneumonidae) on Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) and consequent reduction of production losses were evaluated on caged corn plants in the field. Treatments consisted of plots infested with 0 (control), 15 and 30 pairs of C. flavicincta with egg masses per cage and plot infested without cage and liberation of the parasitoid. Parasitoid release was done when S. frugiperda larvae were three-day-old. Fifty corn plants (40%) per plot were collected seven days after infestation and S. frugiperda larvae present were reared in glass cups on an artificial diet. Number of S. frugiperda larvae was reduced by C. flavicincta but mortality of the pest and parasitoid sex ratio in laboratory were similar among treatments. Total progeny and female production from collected larvae were similar among densities of released parasitoid. Parasitism rate was higher on 30 than on 15 pairs of C. flavicincta. Damage on corn plants at seven and 14 days after S. frugiperda infestation had similar grades at 0, 15 or 30 C. flavicincta pairs and higher values than the plots without cage. Damage by S. frugiperda was lower at 30 C. flavicincta pairs after 21 days of infestation. Final stand, stand reduction by plant death and corn productivity were similar among treatments.

Parasitism of the mite Acarophenax lacunatus on Tribolium castaneum

The objective of this work was to assess the parasitism potential of Acarophenax lacunatus (Cross & Krantz) on Tribolium castaneum (Herbst). The experimental units encompassed Petri dishes containing 25 g of wheat infested with 20 adults of this beetle species. After seven days of infestation, different mite densities (0, 2, 4, 6, 8 and 10 females) were inoculated into the Petri dishes. The increase in mite density led to a linear increase in parasitism, and a consequent reduction in populations of this insect. It is possible to use this mite species in the biological control of T. castaneum.

Induction of systemic resistance in tomato by the autochthonous phylloplane resident Bacillus cereus

The objective of this work was to verify if the induced resistance mechanism is responsible for the capacity of a phylloplane resident bacteria (Bacillus cereus), isolated from healthy tomato plants, to control several diseases of this crop. A strain of Pseudomonas syringae pv. tomato was used as the challenging pathogen. The absence of direct antibiosis of the antagonist against the pathogen, the significant increase in peroxidases activity in tomato plants exposed to the antagonist and then inoculated with the challenging pathogen, as well as the character of the protection, are evidences wich suggest that biocontrol efficiency presented by the antagonist in previous works might be due to induced systemic resistance (ISR).

Scanning electron microscopy of the interaction between Cryptococcus magnus and Colletotrichum gloeosporioides on papaya fruit

The objective of this work was to investigate possible modes of action of the yeast Cryptococcus magnus in controlling anthracnose (Colletotrichum gloeosporioides) on post harvested papaya fruits. Scanning electron microscopy was used to analyze the effect of the yeast on inoculations done after harvest. Results showed that C. magnus is able to colonize wound surfaces much faster than the pathogen, outcompeting the later for space and probably for nutrients. In addition, C. magnus produces a flocculent matrix, which affects hyphae integrity. The competition for space and the production of substances that affect hyphae integrity are among the most important modes of action of this yeast.

Euschistus heros mass rearing technique for the multiplication of Telenomus podisi

The objective of this work was to improve the mass rearing technique of Euschistus heros in laboratory. Nymphs and adults were reared at densities 100, 200, 300 and 400 eggs per Petri dish (9 cm diameter), and at 50, 100, 150 and 200 couples per rearing cages (900 mL), respectively. Survival rate of immature stages and survivorship and reproduction of adults were determinated. Survivorship of nymph to adult was the highest (89%) at density 100 eggs per dish. Adult survivorship was independent of density, and 100 couples per cage were the best to improve quality of the produced progeny. In these conditions, fecundity was 160.8±9.28 eggs per female, and a total of 8,950±456 eggs per cage per month was produced. Two hundred couples per cage showed a negative effect on reproduction, which decreased to 65%. With this technique, a colony of 35 cages with 100 couples per cage yields about 313.3 thousands eggs per month, which is enough to supply the egg parasitoid Telenomus podisi to colonize about 35 ha of soybean field.