Molecular and biological characterization of new isolates of <Emphasis Type="Italic">Cydia pomonella</Emphasis> granulovirus from Iran

The Cydia pomonella granulovirus (CpGV) is a very effective biological control agent of the codling moth, Cydia pomonella L. (Lep.: Tortricidae). Only a few CpGV isolates originating from Mexico (M), England (E), and Russia (R) have been described so far. In a field survey at different locations in Iran, CpGV isolates were collected from single or pooled codling moth larvae. The isolates, designated I1, I7, I8, I15, I22, I28, I30, I66, I67, I68, and I70 showed genetic (DNA restriction endonuclease profiles) and biological (bioassays) differences. Most isolates could be attributed to genome types similar to those found in CpGV-M, -E, and -R. Some of them were clear mixtures of different genotypes. Thus, the CpGV isolates found in the North–West of Iran make an important contribution to the known diversity of CpGV. The occurrence of novel, naturally occurring CpGV isolates emphasize the necessity of further studies towards the diversity and evolution of CpGV.     

The effects of non-host plant extracts on electroantennogram responses,behavior and egg hatching of codling moth, <Emphasis Type="Italic">Cydia pomonella</Emphasis>

The codling moth (Cydia pomonella L.) is a significant pest of pome fruit throughout the world. Behavioral and ovicidal activities of five non-host plant extracts (Arctium lappa, Bifora radians, Humulus lupulus, Verbascum songaricum, Xanthium strumarium), synthetic sex pheromone, (E,E)-8,10-dodecadienol (codlemone), and the plant volatile lure, (2E,4Z)-2,4-decadienoate (pear ester) were evaluated against the codling moth, C. pomonella L. Codlemone elicited the greatest electroantennogram (EAG) response (6.2 ± 1.2 mV) of the compounds tested from male C. pomonella while pear ester elicited 1.7 ± 0.1 mV EAG response in female moths. Codlemone attracted 34.5% of male C. pomonella in olfactometer studies, and it was followed by the X. strumarium extract with 24.8%. There was a significant difference between the behavior of unmated and mated females. V. songaricum extract was the most active extract, attracting 25.4% of unmated females. However, mated C. pomonella females exhibited greatest attraction to pear ester. In a wind tunnel bioassay, combining X. strumarium with codlemone significantly increased the response of male upwind flight and source contact as compared with codlemone alone. All plant extracts, except for V. songaricum, significantly reduced the number of eggs laid. The plant extracts exhibited some toxic effects to eggs, and hatching rate of eggs was reduced as compared with the control. Our results indicate that some of the plant extracts tested are potential candidates for practical use after elucidation and characterization of active compound(s).     

Efficacy baselines of seven insecticides against larvae of Pandemis heparana (Lepidoptera: Tortricidae)

A diet-incorporation larval bioassay was used to evaluate the response of the leafroller Pandemis heparana (Denis and Schiffermüller) to seven insecticides: tebufenozide (Mimic 23% a.i., Bayer), methoxyfenozide (Prodigy 23% a.i., Bayer), flufenoxuron (Cascade 50 DC 4.7% a.i., BASF), lufenuron (Match 5.32% a.i., Syngenta), indoxacarb (Steward WG 30% a.i., Du Pont), abamectine (Vertimec EC 1.9% a.i., Syngenta) and spinosad (Laser 44.2% a.i., Dow Agro Science). Both neonate and 12-day-old (third to fourth instar) larvae were used in the bioassay. The obtained efficacy baselines were compared with the response of the pest exposed to leaves treated with the same insecticides. The persistence of field-aged leaf residues of the seven insecticides was bioassayed on neonate larvae. Given the obtained LC₅₀ values in the diet-incorporation bioassays larval age was not always a significant factor affecting the response of P. heparana larvae. Differences in LC₅₀ values between neonate and 12-day-old larvae were not statistically significant for abamectine, tebufenozide and methoxyfenozide. Young larvae seemed to be more susceptible than older larvae to spinosad, indoxacarb and lufenuron, while flufenoxuron was more effective against 12-day-old than neonate larvae. When the larvae were exposed to the insecticides on treated leaves, all the tested compounds were less effective on older larvae than on neonates. When applied at the recommended field rates, all seven insecticides can be considered highly effective against both neonate and 12-day-old larvae of P. heparana because their security index (SI = recommended field rate/LC₉₀) always exceeded the threshold value of 1. The high persistence of insect growth inhibitors (IGIs) and moulting accelerating compounds (MACs) in the field compensates for their relatively low SI values. For this reason and given their activity against Cydia pomonella, IGIs and MACs are the most interesting insecticides for spring treatments for the combined control of both species, P. heparana and C. pomonella.     

A review： chemical ecology of Ips typographus （Coleoptera, Scolytidae）

Chemical ecology of the spruce bark beetle lps typographus （L.） was reviewed. The outbreak of 1.typographus in central Europe triggered extensive research on chemical ecology, Males initiate host location and produce semiochemicals which attract both males and females, A successful mass attack must first overcome the resistance of the host tree. Pioneer I. typographus evolved to use the resin flow of host trees as kairomones in host location, and synthesized semiochemicals initially to detoxify the resin. If small bark beetle populations infest healthy trees, mass attack is prevented by host resistance, Nine monoterpene alcohols were found in male hind-guts, including cis-verbenol （cV） and 2-methyl-3-buten-2-ol （MB） which are regarded as primary aggregation pheromones, and a low proportion of lpsdienol （ld） which increases attractiveness of cV and MB, Verbenone （Vn） and Ipsenol （le） are anti-aggregation pheromones, that play important roles in adjusting attack density and insect density under the bark. Non-host volatiles are repellent to L typographus, so that beetles do not waste energy boring into non-host trees. The relationship between host resistance, pheromone compounds and behavior, non-host volatiles, bioassays and mass trapping are reviewed, Results of field bioassays stressed that traps baited with specific pheromones could be used as a reasonable protection measure.     

Susceptibility of <Emphasis Type="Italic">Megachile rotundata</Emphasis> to insecticides used in wild blueberry production in Atlantic Canada

The alfalfa leafcutting bee, Megachile rotundata (Fabricius), is a valuable wild and managed pollinator of lowbush blueberry (syn. ‘wild blueberry’, Vaccinium angustifolium Ait.), in Atlantic Canada. As some insecticides may present a hazard to pollinators, we assessed the susceptibility of M. rotundata to insecticides used or projected for future use in lowbush blueberry pest management. In topical direct contact bioassays, adults were susceptible to phosmet, spinosad, spinetoram, and deltamethrin. Based on findings from these laboratory studies, it appears that when used at recommended or projected application rates, each of these compounds poses a hazard to M. rotundata by direct contact. In a second experiment, eggs and larvae were collected in the field and their pollen provisions were treated with deltamethrin, flubendiamide, and spinetoram at field relevant concentrations. Larvae treated with deltamethrin and spinetoram in the laboratory either died before spinning a cocoon or, in the case of spinetoram, occasionally pupated without spinning a cocoon. Flubendiamide was not toxic to adult M. rotundata by direct contact and had no effect on larval survivorship, or time to complete cocoon spinning. Emergence after overwintering was relatively poor overall, but there was no effect of treatment. Based on these results, flubendiamide appears safe to use in the presence of M. rotundata, whereas the other insecticides we tested may pose a hazard.     

Compatibility between <Emphasis Type="Italic">Calpurnia aurea</Emphasis> leaf extract,attraction aggregation,and attachment pheromone and entomopathogenic fungus <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> on viability,growth, and virulence of the pathogen

Metarhizium anisopliae sensu stricto (ss) (Metsch.) Sorok. isolate ICIPE 07 is being developed as biopesticide for the control of ticks. In addition, leaf extracts of Calpurnia aurea Benth, and the attraction aggregation and attachment pheromone (AAAP) are being used as ticks’ attractant. The three agents are being considered for use in combination in an autodissemination approach, whereby ticks that are attracted to semiochemicals are infected with the inoculum. Experiments were therefore conducted to evaluate in vitro the compatibility between C. aurea, AAAP, and the M. anisopliae on vegetative growth, conidial production, and spore viability. Calpurnia aurea leaf extract was compatible with the fungus at all the concentrations tested, whereas AAAP inhibited all the fungal growth parameters. The virulence of M. anisopliae formulated in emulsifiable extracts of C. aurea was also tested against different developmental stages of Rhipicephalus appendiculatus in laboratory bioassays. No significant differences in virulence were observed between M. anisopliae applied alone and M. anisopliae formulated in different concentrations of C. aurea leaf extracts. These results suggest that C. aurea leaf extracts is compatible with M. anisopliae and could be mixed together for “spot-spray” treatments as low-cost and environmental-friendly technology to control ticks in grazing field, while AAAP should be used separately.     

Über Parasitierung und Farbformen des LärchenbockesTetropium gabrieli Weise (Col., Cerambycidae) in Südtirol

In June of 1984 lying stems of larch trees were heaveliy attacked by the larch cerambycidT. gabrieli near Brixen/South Tyrol. From 229 larvae 134 adultTetropium and 95 larval parasites (=41%) emerged. The parasite species were:Rhimphoctona lucida Clém. (Hym., Ichneum.) 55 indiv.;Helcon dentator F. (Hym., Bracon.) 1 indiv., andBillaea triangulifera Zett. (Dipt., Tachin.) 39 indiv. These results are compared with those got bySchimitschek (1929) in ?SR and Lower Austria. Furthermore the different colour formes of the population ofTetropium occurred near Brixen are examined.     

Allelopathy assessments for the environmental biosafety of the salt-tolerant transgenic Eucalyptus camaldulensis, genotypes codA12-5B, codA 12-5C, and codA 20C

Allelopathy tests were conducted on salt-tolerant transgenic eucalyptus trees conferring bacterial codA gene in the designated net-house conditions under Type II use (contained use) of the Japanese law on environmental biosafety aiming for Type I (field use) application. Three transgenic and corresponding nontransgenic genotypes were employed for four different tests: (1) sandwich bioassay; (2) soil germination method; (3) gas chromatography (GC) for volatile substances from the plants; and (4) high-performance liquid chromatography (HPLC) on phenolic compounds from fresh leaves, which are the primary allelopathic substances on the species. The simple approaches, the bioassays, indicated no significant difference between the transgenic and nongenetically modified genotypes. There was no qualitative difference between the transgenic and nontransgenic lines by GC or HPLC. Absence of any quantitative difference was suggested by repetitive examination and subsequent analysis of variance assessments with the chromatographic methods and bioassays. Moreover, it was also indicated that bioassays should be the primary assessment method for allelopathy in considering the simplicity, speed, low cost, and reproducibility of these methods. Overall, substantial equivalence was considered on the three transgenic genotypes with codA gene when compared with the nontransgenic Eucalyptus camaldulensis lines. The experiments supported the application to isolated field testing of the transgenic Eucalyptus camaldulensis genotypes as the first case and experience in Japanese regulatory approval processes Type I Use for the deliberate release to the environment.     

Jungraupen des Goldafters und Forficuliden als Schädlinge an Früchten von Birne und Apfel

Zusammenfassung Es wird über das starke Auftreten des Goldafters (Euproctis chrysorrhoea L.) 1970 im Raume Halle Leipzig berichtet, wobei auf den Fraß der Jungraupen an Früchten von Birne hingewiesen wird, der bislang noch nicht bekannt war. Diese Fraßbilder können leicht mit denen der Räupchen des Fruchtschalenwicklers (Adoxophyes reticulana Hb.) verwechselt werden.Während diese Schädlinge die Fruchtschale angreifen,benutzen die Forticuliden die Bohrgänge des Apfelwicklers (Laspeyresia pomonella L.) um in das Innere der Früchte zu gelangen und überwiegend im Bereich des Kerngehäuses zu minieren.

---

Summary A report is given of the frequent occurence of the butterfly(Euproctis chrysorrhoea L.) during 1970 in the Halle-Leipzig area, and attention is drawn to the damage caused by young caterpillars to pear-fruit, a phenomenon unknown so far. The type of damage may easily be sonfused with that caused by the caterpillars of the fruit-shell tortricides(Adocophyes reticulana Hb.).Whereas these pests attack the fruit-shell, theforficulides use the holes bored by the apple-grub(Laspeyresia pomonella L.) to reach the inside of the fruit and to eat their way mainly through the core.Résumé En 1970, on a rapporté sur l'immense apparition du cul-doré(Euproctis chrysorrhoea L.) dans le district de Halle-Leipzig, et, en même temps, on indique la voracité des jeunes chenilles attaquant les fruits, ce qui n'était pas encore connu jusqu'à présent. On peut facilement prendre ces indices de mangeures pour ceux des petites chenilles de la pelure-tortrice(Adoxophyes leticulana Hb.).Quand ces insectes nuisibles attaquent la pelure, lesforficulides se servent des chemins percés de la pomme-tortrice pour arriver dans l'intérieur des fruits et pour se caver avant tout dans la région du trocon.

     

Dynamic adsorption of α-pinene and linalool on silica nanoparticles for enhanced antifeedant activity against agricultural pests

The terpene compounds, α-pinene and linalool were formulated with silica nanoparticles (SNPs) by a simple immersion method and the antifeedant activity of these formulations was evaluated against two major agricultural pests, the tobacco cutworm (Spodoptera litura F.) and the castor semilooper (Achaea janata L.) in laboratory bioassays. The interaction between terpenes and SNPs, shelf-life, suspension stability as well as the bioactivity of the nanoformulations were also studied. Both these terpenes in their pure form are known to deter feeding in several lepidopterous insects. However, formulating these pure terpene compounds with nano silica enhanced their biological activity up to 25 times to S. litura. Fourier transform infrared spectroscopy analysis of these nano botanical formulations indicated the presence of hydrogen bonding between terpenes and the surface of SNPs. Transmission electron microscopy images confirmed the higher aggregation property of the SNPs. Suspension studies validated the improved shelf-life of the nano-biocomposites, while X-ray diffraction (XRD) revealed the amorphous nature of formulations and no crystalline impurities. Adsorption of α-pinene and linalool onto SNPs resulted in an effective formulation that enhanced the antifeedant potential of the individual terpenes against insects while producing longer shelf-life for the terpenes.     

Zum Auftreten der Gammaeule,Phytometra (Plusia) gamma L.

Zusammenfassung Es wird über das Auftreten der Gammaeule(Phytometra gamma L.) in den Jahren 1959, 1961 und 1962 berichtet. Aufgrund von Fangergebnissen an Insekten-Fanglampen und nach Beobachtungen im Freiland sowie in Zuchtk?figen, werden einige biologische Besonderheiten er?rtert. Als Parasiten traten auf: der PilzTarichium sp., die Raupenfliegen (Tachinen)Voria ruralis Fall.,Platymyia westermanni Zett. sowie eine nicht n?her bestimmte Ichneumonide. über Erfahrungen bei der Bek?mpfung der Gammaeule wird berichtet.

---

Summary There has been reported on the appearance ofPhytometra gamma L. in 1959, 1961 and 1962. On the evidence of catching results at Insect-light-traps and in consequence of observations in the open air as well as in breeding cages, some biological particularities are argued. As parasites there appeared: the fungusTarichium sp., the „Raupenfliegen” (Tachinen)Voria ruralis Fall.,Platymyia westermanni Zett. and also an Ichneumonide that has not been determined strictly. Concerning the experiences on the control of the common silver moth a report will be given.

---

Résumé On a rapporté sur l'apparition dePhytometra gamma L. en 1959, 1961 et 1962, En conséquence des reśultats de trappe avec des trappes-lumières pour les insectes et après des observations en plein air, ainsi que dans les cages pour l'élévation, quelques particularités biologiques ont é té discuté. Comme parasites appar?rent: Le champignonTarichium sp., les „Raupenfliegen” (Tachinen)Voria ruralis Fall.,Platymyia westermanni Zett., ainsi qu'une Ichneumonide pas encore déterminée à peu près. Des experiences sur la lutte contre Noctuelle grise seront rapportées.

     

Using degree-day accumulations and host phenology for predicting larval emergence patterns of the olive psyllid, <Emphasis Type="Italic">Euphyllura phillyreae</Emphasis>

The olive psyllid, Euphyllura phillyreae Foerster is one of the most destructive pests on buds and flowers of olive tree (Olea europaea L.) in May when the olive growers cannot apply any insecticides against the pest. Temperature-dependent development of the psyllid was studied at constant temperatures ranged 16–26°C. A degree-day (DD) model was developed to predict the larval emergence using the weekly cumulative larval counts and daily mean temperatures. Linear regression analysis estimated a lower developmental threshold of 4.1 and 4.3°C and a thermal constant of 164.17 and 466.13 DD for development of egg and larva, respectively. The cumulative larval counts of E. phillyreae approximated by probit transformation were plotted against time, expressed as the sum of DD above 4.3°C, the starting date when the olive tree phenology was the period of flower cluster initiation. A linear model was used to describe the relationship of DDs and probit values of larval emergence patterns of E. phillyreae and predicted that 10, 50 and 95% emergence of the larvae required 235.81, 360.22 and 519.93 DD, respectively, with errors of 1–3 days compared to observed values. Based on biofix depends the development of olive tree phenology; the DD model can be used as a forecasting method for proper timing of insecticide applications against E. phillyreae larvae in olive groves.     

Toxicity of some pesticides against the egg stage and the first larval instar of the chrysopid predatorChrysoperia carnea (Steph.)

The toxicity of cypermethrin, deltamethrin, fenpropathrin, fenvalerate, methomyl and kelthane-s against the egg stage and the 1st larval instar ofChrysoperla carnea (Steph.) revealed that deltamethrin exhibited magnitude bad side effects against the eggs (LC₉₀=3.35 ppm) as compared with the safest compound kelthane-s (LC₉₀=144 ppm); the figures of the other tested toxicants ranged between 17.6 and 109.2 ppm.It was found that the larval stage needed higher concentrations to achieve similar mortality percentages. LC₉₀ values ranged between 72.2 and 1,176 ppm. Ranking of toxicity was, however, similar to that of ovicidal action.With one table     

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. An erratum to this article is available at .     

Laboratory evaluation of the effectiveness of the entomopathogen; <Emphasis Type="Italic">Isaria farinosa,</Emphasis> on citrus mealybug, <Emphasis Type="Italic">Planococcus citri</Emphasis>

Citrus mealybug Planococcus citri (Risso) (Hemiptera: Pseudococcidae) is one of the main pests on citrus trees. Biological control of the pest is based on the release of hymenopterous parasitoids and coccinellid predators at present. The effectiveness of entomopathogen fungus Isaria farinosa (Holmsk.) Fries ([Sordariomycetes: Hypocreales] (Syn: Paecilomyces farinosus), as an alternative biological control agent on citrus mealybug, was investigated using four different inoculum densities and different relative humidities (RH). The entomopathogen caused 89.39% mortality in ovisacs, 84.07% mortality in second larval stage, 84.53% mortality in adult females, and 78.71% mortality in first larval stage at 95% RH and at 1 × 10⁸ conidia ml⁻¹ inoculum concentration. Percent mortalities were between 50 and 60 in ovisac, first and second larval stage at 95% RH and at 1 × 10⁷ conidia ml⁻¹. Percent mortality was decreased parallel to the decrease in humidity level and inoculum densities; however, the fungus caused significant infection in 70% and 80% RH. These results demonstrated that the effectiveness of the entomopathogen is promising for biocontrol of citrus mealybug.     

Behaviour-modifying activity of eugenol on Thrips tabaci Lindeman

A series of observational bioassays were conducted to investigate the behavioural responses of the onion thrips, Thrips tabaci Lindeman (Thysanoptera: Thripidae), to an application of a secondary plant compound to two different host plants with dissimilar leaf surface characteristics. Eugenol, a phenylpropanoid compound known to deter feeding and oviposition of the onion thrips, was applied to leek (Allium porrum L.) and cucumber (Cucumis sativus L.) at 1% concentration. Using a video system and special software for computing observational data, influences of this plant compound on the behaviour of T. tabaci females were evaluated. Eugenol treatment significantly prolonged the time periods thrips spent being inactive and moving across the treated leek or cucumber surface. The feeding periods on leek leaves treated with eugenol were clearly shorter compared to periods on untreated leek. The behaviours related to oviposition on leaves from both host species treated with eugenol were slightly reduced. T. tabaci females avoided direct contact with eugenol particularly when applied to leek, showing significantly lower contact duration compared to an untreated surface. This shows that behaviour-modifying secondary compounds such as eugenol may be used in various strategies and may contribute to the enhancement of current biological control measures and/or form novel components of Integrated Pest Management strategies.     

Impact of geochemical composition of diatomaceous earth on its insecticidal activity against adults of <Emphasis Type="Italic">Sitophilus oryzae</Emphasis> (L.) (Coleoptera: Curculionidae)

Laboratory experiments were done to determine the effect of geochemical composition of diatomaceous earth (DE) on insecticidal activity of DE against adults of the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae). Samples of DE were mined from DE-deposits in Slovenia, Greece, and Serbia. In addition, a commercially available DE formulation (SilicoSec^®) was used in the tests and served as a positive control. The bioassays were carried out at temperatures 20, 25, and 30°C, relative humidity levels of 55 and 75%, and at application rates of 100, 300, 500, and 900 ppm. Adult mortality was recorded after 7, 14, and 21 days of exposure. Prior to bioassays with S. oryzae, the geochemical composition of all DEs that were used in the tests was determined by whole rock ICP geochemical analyses. Silica (in the form of SiO₂ or opal-A) was the DE ingredient that was significantly correlated with efficacy in most of the bioassays. Some weak positive correlation was observed between S. oryzae mortality and MnO or CaO content. All significant correlations between mortality and Al₂O₃, Fe₂O_3, K₂O, TiO₂, Cr₂O₃, P₂O₅, and MgO content were negative, while correlation between Na₂O content and mortality was generally not significant.     

Assessing toxicity of post-emergence herbicides to the Spilarctia obliqua Walker (Lepidoptera: Arctiidae)

The lethal and sublethal effects of three post-emergence herbicides, 2,4-D ethyl ester (Weedkill 80WP), imazethapyr (Pursuit 10EC) and quizalofop ethyl (Tergasuper 5EC) fortified with artificial diets were studied on larvae of Spilarctia obliqua Walker (Lepidoptera: Arctiidae). Quizalofop ethyl and imazethapyr caused significant reduction of pest survival at almost all levels; however, 2,4-D ethyl ester was nontoxic. Interestingly, LC₅₀ data (0.230 and 0.855% for quizalofop ethyl and imazethapyr, respectively) obtained from probit analysis were almost equal to labeled doses (x) of quizalofop ethyl (x = 0.16%) and imazethapyr (x = 0.625%), which shows the high toxicity of these compounds against S. obliqua larvae. Among the three herbicides, imazethapyr caused sublethal effects on this pest, increasing the larval period at almost all concentrations tested in the artificial diet. Considering the markedly significant effect of quizalofop ethyl on pest survivorship with no sublethal effect, we suggest incorporating it into the integrated pest management module for S. obliqua in legumes or oilseed crops with other biorational insecticides. Based on toxicity, imazethapyr can be a potential candidate for integrated management of S. obliqua. However, because of its sublethal effects, we advocate caution while using it in the presence of pest infestations.     

Herbaceous weed control in conifer plantations with hexazinone and nitrogen formulations

In order to determine if herbicide efficacy is affected by nitrogen fertilizer, the influence of different nitrogen fertilizers applied in different combinations with hexazinone formulations were evaluated on herbaceous weed communities. Field studies comparing three application methods in conifer plantations showed greatest reduction in total weed cover with a co-granular formulation of hexazinone and triamino-s-triazine. Slightly less control was achieved with separate applications of liquid hexazinone and triamino-s-triazine granules, and poorest control with granular urea followed by liquid hexazinone. Weed control increased with an increase in hexazinone rate. Statistical analysis of the effect on conifers showed that the highest hexazinone rate significantly increased survival of noble fir (Abies procera Rehd.) and stem diameter of both noble fir and Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and that the highest nitrogen rate significantly decreased survival of both species but did not affect stem diameter. Survival of noble fir and diameter of both noble fir and Douglas-fir were significantly increased where a co-granular formulation of hexazinone and triamino-s-triazine granules was used.     

Structural and Biometric Characterization of Nothofagus betuloides Production Forests in the Magellan Region,Chile

Summary

This study, in die Chilean Magellan Region, undertook the structural and biométrie characterization of Nothofagus betuloides (Mirb.) Blume (coihue de Magallanes) production forests to provide information for sustainable forest management. Six locations were surveyed, five on the continent and one on Tierra del Fuego Island. A total of 6,102 ha were photointerpreted and then checked and described in the field according to their location, environmental characteristic, and vegetation type. The degree of disturbance, stage of development, status of regeneration, and composition and cover of the understory were also described. From the surveyed locations, a total of 3,807 ha were production forests of which a 76% area had Nothofagus pumilio (lenga) and N. betuloides mixed forests. The remaining areas (24%) were pure N. betuloides forests. Nondisturbed, old-growth forests covered 47% of the surveyed area. The remaining area (53%) had some disturbance. In the nondisturbed forests, mean volume stocks were 438 m³ ha^-1, and in disturbed forests, mean volume stocks were 316 m³ ha^-1.