MSPD procedure combined with GC-MS for the determination of procymidone, bifenthrin, malathion and pirimicarb in honey

A method based on matrix solid-phase dispersion and gas chromatography-mass spectrometry to determine procymidone, malathion, bifenthrin and pirimicarb in honey is described. The best results were obtained using 1.0 g of honey, 1.0 g of silica-gel as dispersant sorbent and acetonitrile as eluting solvent. The method was validated by fortified honey samples at three concentration levels (0.2, 0.5 to 1.0 mg kg-1). Average recoveries (n=7) ranged from 54 to 84%, with relative standard deviations between 3.7 and 8.5%. Detection and quantification limits attained by the developed method ranged from 0.02 to 0.08 mg kg-1 and 0.07 to 0.25 mg kg-1 for the honey, respectively.

Preliminary data on Brazilian monofloral honey from the northeast region using FT-IR ATR spectroscopic, palynological, and color analysis

Fourier transform infrared attenuated total reflectance (FT-IR ATR) spectroscopy was used to determine 14 different measurands in northeast Brazilian honey samples. Nine different honey samples (six monofloral and three polyfloral) from 2009 obtained from the company CEARAPI underwent FT-IR ATR, palynological, color, and sensorial analysis to obtain preliminary results for these types of honey. The results showed that there are five monofloral, three bifloral, and one extrafloral honey, and also that mid-infrared spectrometry can be used as a screening method for the routine analysis of Brazilian honey, with the advantages of being rapid, nondestructive, and accurate.

Natural colonization of leaves of 'Pêra' sweet orange and related varieties by Guignardia citricarpa

The purpose of this research was to evaluate the differences in the colonization and production of structures in the leaves of 'Pêra' sweet orange (Citrus sinensis) clones and related varieties by Guignardia citricarpa. The natural colonization and the production of reproductive structures in the leaves and in vitro of ten 'Pêra' sweet orange was quantified in the following clones: Bianchi, Dibbern C.V., EEL, IAC 2000, Olímpia 15161, Premunizada 1212, Premunizada 1743/82, R. Gullo 1569/244, R. Gullo 1570/246 and Vimusa; and in five related varieties: Redonda C.N, Ovale 968, Ovale San Lio 969, Lamb Summer and Corsa Tardia. The quantification of the colonization density of G. citricarpa in the leaves was obtained through isolation. Incidence and colonization density (cm²) were calculated for each clone. The production of reproductive structures was accomplished through the moistening and drying process of the leaves. The incidence (percentage of affected leaves) and the leaf surface percentage occupied by the reproductive fungus structures were quantified. The in vitro production of reproductive structures was accomplished in water-agar medium. The number of immature and total reproductive fungus structures (cm²), and the percentage of picnidia with liberation of spores were quantified. Significant differences were not observed among clones related to the colonization of the leaves. But there were differences in the induction experiments, i.e., in the leaf surface percentage occupied by the reproductive fungus structures and the in vitro production of reprodutive fungus structures.

Effect of temperature, leaf wetness, and rainfall on the production of Guignardia citricarpa ascospores and on back spot severity on sweet orange

The black spot of citrus (Citrus sp.) is caused by Guignardia citricarpa with ascospore production depending on temperature, leaf wetness, and rainfall. The number of ascospores produced was monitored using a spore trap and climatic factors were recorded using an automated meteorological station of 'Natal' and 'Valencia' sweet orange (Citrus sinensis) orchards in Mogi Guaçu in the state of São Paulo, Brazil, from November 2000 to March 2001. The fruits were bagged to prevent infection and the bags removed from different sets of fruit for one week during each of the 18 weeks of the season in both orchards. Ascospores were produced during the entire experimental period, from spring through summer, primarily after rain events. In both orchards, ascospore production reached a peak in January and February. Ascospore production was related to leaf wetness only in the Natal orange orchard but was not related to total rainfall or temperature in either orchard. Disease was most severe on fruit exposed the 7th, 8th, and 13th weeks after beginning the experiment in both cultivars as well as after the 16th week for 'Natal'. There was a strong relationship between disease severity and total rainfall for both orchards and a weak correlation between temperature and severity in the 'Natal' block only. There was no relationship between severity and leaf wetness or ascospore numbers.

Susceptibility of fruits of the 'Valência' and 'Natal' sweet orange varieties to Guignardia citricarpa and the influence of the coexistence of healthy and symptomatic fruits

The importance of the presence of symptomatic fruits with citrus black symptoms (CBS) on the disease severity level in subsequent crop production was assessed in an orchard planted with Valência and Natal sweet orange varieties. Additionally, the period of susceptibility of the fruits of these varieties was evaluated. Fruits were covered with paper bags at the stage of 75% fallen petals and were then exposed to natural infection at weekly intervals, from October 2000 to April 2001. This process was carried out in plants where the fruits from the previous harvest had been picked as well as in plants where fruits remained until natural drop. The evaluation of disease severity used a scale that varied from 0 (absence of symptoms) to 6 (severe symptoms). It was observed that, for the Valência and Natal varieties, conidia of Phyllosticta citricarpa that had formed on the lesions of fruits from the previous harvest did not significantly increase the severity of disease on the fruits of the subsequent harvest period. In this study, the protection of the fruits until 10 weeks after petal drop did not affect the number of lesions, indicating that ascospore discharges after that date were, probably, responsible for disease severity. Fruits exposed between the 20th and 24th week after 75% of the petals had fallen were symptomatic, indicating that, at this stage, the fruits were still susceptible to the pathogen.

Orange rust in sugarcane: molecular identification in Rio de Janeiro State

Sugarcane (Saccharum spp.) cultivation is one of the major agricultural activities in the Brazilian states. This study aimed to molecularly identify the pathogen associated with rust in sugarcane cultivars in the state of Rio de Janeiro and to suggest a control strategy. Among the 14 PCR-tested cultivars, Puccinia kuehnii infection was identified for RB947520, RB92606, RB835486, RB72454, SP89-11I5, SP83-2847, both from infected leaf sample and from urediniospores. Puccinia kuehnii was not detected by PCR for the cultivars RB955971, RB951541, RB92579, RB867515, RB855536, SP91-1049, SP80-3280, SP80-1816. This is the first molecular detection of this fungus in the state of Rio de Janeiro for six of the 14 analyzed cultivars.

Stability of Citrus tristeza virus protective isolate 'Pêra IAC' according to SSCP analysis of old and new lines of three sweet orange varieties

Clonal cleaning, followed by pre-immunization with protective complexes of Citrus tristeza virus(CTV), allowed the commercial cultivation of Pêra sweet orange, a variety that has great importance for Brazilian citriculture but is sensitive to the virus. The use of mild protective isolates in other citrus varieties, even those more tolerant to CTV, can also be of interest to prevent the spread of severe isolates. The aim of this study was to characterize, by means of SSCP (Single Strand Conformational Polymorphism) analysis of the coat protein gene, CTV isolates present in plants of the sweet orange cultivars Pêra, Hamlin and Valencia propagated from four budwood sources: 1) old lines, 2) nucellar lines, 3) shoot-tip-grafted lines, and 4) shoot-tip-grafted lines pre-immunized with the mild CTV protective isolate 'PIAC'. We also evaluated the correlation of the obtained SSCP patterns to stem pitting intensity, tree vigor and fruit yield. SSCP results showed low genetic diversity among the isolates present in different trees of the same variety and same budwood source and, in some cases, in different budwood sources and varieties. Considering tristeza symptoms, lower intensity was noted for plants of new, shoot-tip-grafted and pre-immunized shoot-tip-grafted lines, compared to old lines of the three varieties. The observed SSCP patterns and symptomatology suggested that more severe CTV complexes infect the plants of old lines of all three varieties. The protective complex stability was observed in the SSCP patterns of CTV isolates of some shoot-tip-grafted and pre-immunized clones. It was concluded that the changes detected in other electrophoretic profiles of this treatment did not cause loss of the protective capacity of CTV isolate 'PIAC' inoculated in the pre-immunization.

Effect of trickle irrigation on root development of the wet bulb and 'pera' orange tree yield in the state of São Paulo, Brazil

The aim of this study was to evaluate the effect of different microirrigation designs on root system distribution in wet bulb region, orange orchard yield and quality of orange fruits. The experiment was installed as random blocks with five treatments and four replicates in an orchard of 'Pêra' orange trees grafted on 'Cleopatra' mandarin rootstock. The treatments consisted of: one drip line (T1), two drip lines (T2), four drip lines (T3) per planting row, microsprinkler irrigation (T4) and without irrigation (T5). Irrigation treatments favored yield and ºBrix. The treatment with a single drip line (T1) showed the greatest quantity of roots in relation to the treatments T2 and T3.

Estimation of transpiration of the 'Valencia' orange young plant using thermal dissipation probe method

Most studies on measures of transpiration of plants, especially woody fruit, relies on methods of heat supply in the trunk. This study aimed to calibrate the Thermal Dissipation Probe Method (TDP) to estimate the transpiration, study the effects of natural thermal gradients and determine the relation between outside diameter and area of xylem in 'Valencia' orange young plants. TDP were installed in 40 orange plants of 15 months old, planted in boxes of 500 L, in a greenhouse. It was tested the correction of the natural thermal differences (DTN) for the estimation based on two unheated probes. The area of the conductive section was related to the outside diameter of the stem by means of polynomial regression. The equation for estimation of sap flow was calibrated having as standard lysimeter measures of a representative plant. The angular coefficient of the equation for estimating sap flow was adjusted by minimizing the absolute deviation between the sap flow and daily transpiration measured by lysimeter. Based on these results, it was concluded that the method of TDP, adjusting the original calibration and correction of the DTN, was effective in transpiration assessment.

Color change and quality response of ‘lane late’ orange submitted to degreening process

This study aimed at evaluating the effects of ethylene on peel color and compositional changes in ‘Lane late’ orange stored under refrigerated and ambient conditions. Physiologically mature, but green-peeled, oranges were exposed to ethylene gas under room temperature and high relative humidity for 24 hours. Storage chamber was ventilated with fresh air after 12 hours to mitigate consequences derived from fruit respiration. Both nondestructive analysis, such as peel color (hue angle, chromaticity, and brightness) and weight loss, and destructive ones (soluble solids, titratable acidity, pH, soluble solids to acidity ratio, and puncture force) were performed upon harvest, after degreening, and every three days during eighteen days in storage. Experiment was carried out using an entirely randomized design with thirty replications for nondestructive and four replications for destructive analyses, in a split plot scheme. Exposure to ethylene ensured a golden yellow peel for both fruit stored under ambient and refrigerated conditions. High relative humidity, associated with low temperature prevented fruit from losing moisture. Fruit exposure to ethylene did not affect weight loss, soluble solids, titratable acidity, pH, soluble solids, acidity ratio, or puncture force.

Mechanical damage during harvest and loading affect orange postharvest quality

Brazil is the world’s largest orange producer; however, part of this production is lost during postharvest. This loss can be minimized by controlling incidence of physical damage throughout the harvest and loading operations. Impacts can negatively modify quantitative and qualitative fruits aspects. The main goal of this study was to measure the impact magnitude in two types of harvest (manual and detachment) and during all steps from picking into bags until loading for transport to the processing industry and additionally evaluating, in laboratory, the physico-chemical quality of the fruit subjected to various impacts, similar to those found in the field. In order to evaluate the impact magnitude, an instrumented sphere was used (760 mm, Techmark, Inc, USA). The following physico-chemical parameters were evaluated during 6-days of storage: weight loss, soluble solids contents, titratable acidity, ascorbic acid content, pH, firmness and peel color. The greatest impacts were observed during harvest, during the detachment practice, and when loading and unloading from bulk storage, with average acceleration values between 249.5 and 531.52G. The impact incidence in oranges were responsible for reducing the soluble solids, titratable acidity, ascorbic acid and weight by to 5.5%; 8.7%; 4.6% and 0.5%, respectively, compared to the control. Impacts during harvest and the various pre-industry manipulation steps must be controlled as they interfere in postharvest quality and physiology of ‘Valência’ oranges.

Growth and development of honey weed based on days or thermal units

This work was carried out with the objective of evaluating the growth and development of honey weed (Leonurus sibiricus) based on days or thermal units (growing degree days). Thus, two independent trials were developed to quantify the phenological development and total dry mass accumulation in increasing or decreasing photoperiod conditions. Considering only one growing season, honey weed phenological development was perfectly fit to day scale or growing degree days, but with no equivalence between seasons, with the plants developing faster at increasing photoperiods, and flowering 100 days after seeding. Even day-time scale or thermal units were not able to estimate general honey weed phenology during the different seasons of the year. In any growing condition, honey weed plants were able to accumulate a total dry mass of over 50 g per plant. Dry mass accumulation was adequately fit to the growing degree days, with highlights to a base temperature of 10 ºC. Therefore, a higher environmental influence on species phenology and a lower environmental influence on growth (dry mass) were observed, showing thereby that other variables, such as the photoperiod, may potentially complement the mathematical models.

Pollination and fruit set in pumpkin (Cucurbita pepo) by honey bees

Species of Cucurbitaceae are cultivated worldwide and are depend on bee pollination for fruit set. Field and lab experiments were conducted at Cornell University, Ithaca, NY, during 1996 and 1997 to determine "Howden" pumpkin (Cucurbita pepo L.) pollen removal and deposition by honeybees and factors relating to male flower attractiveness. Several parameters were evaluated in flowers at anthesis: (1) removal of pollen from anthers by honey bees, (2) pollen deposition on the stigma by honey bees, (3) amount of pollen on the body of honey bees, (4) fruit set after bee pollination, and (5) male flower nectary's pores and flower attractiveness. Honey bees carried between 1,050 to 3,990 pollen grains and 13,765 were removed from an anther after one visit. The amount of pollen deposited on the stigma by the honey bees varied according to the number of visits, from 53 grains with one visit, to 1,253 grains with 12 visits, and the mean number of grains in each visit varied from 53 to 230 grains. The percentage of established fruits was higher (100%) when the flowers received 12 visits of Apis mellifera, corresponding to a load 1,253 pollen grains. The attractiveness of the male flower for pollen and nectar collection was increased by the degree of opening of the access pore to the nectary in the flower.

Pollen analysis of honey and beebread derived from Brazilian mangroves

Pollen analyses were performed on honey and beebread from hives in apiaries located in two distinct mangrove areas dominated by Laguncularia racemosa (L.) C.F. Gaernt. One apiary was located at the edge of Guanabara Bay, Rio de Janeiro State, and the other near Maranguá Bay, Bahia State, Brazil. We investigated the contribution of nectar and pollen from mangrove vegetation to Apis mellifera L. honey and beebread stocks. Intensive visitation to this plant species by honeybees and the presence of its pollen grains in honey and beebread confirmed the importance of Laguncularia racemosa as a polliniferous and nectariferous species.

Sex determination in honey bees (Apinae and Meliponinae) and its consequences

The first experiments on sex determination in bees began with Dzierzon, Meves, Nachtsheim, Paulcke, Petrunkewitsch, Manning. Whiting, (1943) found multiple alleles in Bracon xo that are the Rosetta stone of sex determination in Hymenoptera. Whiting also discovered that some species of microhymenoptera do not possess xo sex alleles. Therefore, Hymenoptera apparently presents two types of sex determination superimposed on haplodiploidy. In the panmictic groups hemizygous (xo1, xo2,... xon) and homozygous (xo1xo1, xo2xo2... xonxon) are males while heterozygous (xo1xo2, ... xon-1xon) are females. There is no such series of xon in endogamous Hymenoptera, since the constant elimination of diploid males would be damaging to the population and the mutation of xo to xon would be quickly eliminated. Besides the Whiting hypothesis, four others are discussed. The new hypothesis of genomic imprinting, of Beukeboom, is eliminated since: a) spermatozoa that develop within the egg produce male tissue; b) telitokous parthenogenesis due to the fusion of two haploid cells develop into females; c) last instar larvae treated with juvenile hormone become queens. The Cunha and Kerr hypothesis (female determining genes are totally or partially additive and male determination is totally or partially nonadditive) explains all known cases. The xo is a female determining gene. Sex determination in social bees led to the gradual evolution of two systems of caste determination: one in which queens and workers are similar and males are very different (Apinae), and another in which workers and males are very similar and both very different from the queens (Meliponinae). This second system in stingless bees implies that many of the mutations that improve worker capacities also affect the males that will carry out some activities that in Apis are clearly female ones. Ten of these activities are described.