Methods for the Quantification of Resistance of Apple Genotypes to European Fruit Tree Canker Caused by Neonectria ditissima.

European fruit tree canker, caused by Neonectria ditissima, is an important disease of pome fruit worldwide. Apple cultivars differ in their levels of susceptibility to N. ditissima. In order to design an effective plant resistance test, we examined the effectiveness of two resistance parameters: infection frequency and lesion growth. Both parameters were evaluated in parallel tests using 10 apple cultivars in three experimental years, applying seminatural infection of leaf scars (infection frequency) or inoculation of artificial wounds (lesion growth). We compared six parameters for lesion growth, of which a new parameter, lesion growth rate (LGR), appeared to be the best with respect to reproducibility and statistical significance. LGR is defined as the slope of the regression of lesion size versus time. The slope was estimated for each lesion, employing a common start date and a lesion-specific end date determined by the girdling of the lesion. The two parameters (infection frequency and LGR) were examined in separate experiments and in three successive years, and provided complementary information and resulted in reproducible conclusions on the relative resistance levels to N. ditissima of the tested cultivars. The presented methods can be used to develop strategies for the control of European fruit tree canker (e.g., in the breeding of new apple cultivars with high levels of resistance to N. ditissima).

Bacterial canker of plum trees, caused by Pseudomonas syringae pathovars, as a serious threat for plum production in the Netherlands.

In the Netherlands, bacterial canker in plum trees (Prunus domestica) is a serious and recent problem in plum production. It is caused by Pseudomonas syringae pathovars syringae and morsprunorum. The trunks of the affected plum trees are girdled by bacterial cankers resulting in sudden death of infected trees in 3-4 years after planting. Disease incidences can be very high, and sometimes complete orchards have to be removed. Recently, plum cultivation in the Netherlands has changed from a relatively extensive into an intensive cultivation. However, due to the risks of losses of trees due to bacterial canker, growers are reluctant to plant new plum orchards. In general nurseries and fruit growers are not familiar with bacterial diseases and lack knowledge in order to prevent infections. Therefore, control strategies to manage plum decline have to be developed.

Use of potassium bicarbonate (Armicarb) on the control of powdery mildew (Sphaerotheca mors-uvae) of gooseberry (Ribes uva-crispa).

Powdery mildew (Sphaerotheca mors-uvae) severely infects young shoots, stems and fruits of gooseberry (Ribes uva-crispa). Environmental friendly and biological control measures are being sought throughout the world. Especially in organic gooseberry growing effective control measures are needed, because powdery mildew infections may result in a total loss of the crop. In organic currant growing the number of adequate control methods is very limited. Sulphur as a fungicide against powdery mildew in e.g. gooseberry or table grape growing is not recommendable due to possible bleaching of berries and scorching of tender shoots. Various bicarbonate salts are suggested as a good option to control powdery mildew. In a field trial the effect of potassium bicarbonate (Armicarb) on the on the control of powdery mildew of gooseberry was evaluated. Four treatments; i.e. two preventive strategies and two curative strategies, were applied. PLants were sprayed until runoff. The percent of infected fruits and disease severity were assessed. In the unsprayed control plots very high disease incidences were observed; on average more than 90% of the berries were infected with powdery mildew. The weekly (preventive) spray applications with potassium carbonate reduced the disease incidences on fruits significantly. On average approximately 10% of the fruits were affected by powdery mildew. However, the number of spray applications was high. In conclusion, our results indicate that applications of potassium bicarbonate (as Armicarb) are effective in reducing the incidence and severity of American powdery mildew in gooseberry. Early spray applications are necessary to protect berries against powdery mildew infections. Future research will focus on reducing the number of applications, e.g. warning models based on powdery mildew of rose (Sphaerotheca pannosa).

Advanced spraying techniques in fruit growing--the ISAFRUIT project--towards safer and better quality of fruit.

In 2006 the project ISAFRUIT (www.isafruit.org)--"Increasing fruit consumption through a trans disciplinary approach leading to high quality produce from environmentally safe, sustainable methods"--was launched within the 6th Framework Program of the EC. Within the project's work package ECOFRUIT (WP 5.1 - Safe European fruit from a healthy environment) a Crop Adapted Spray Application (CASA) system is developed. This system is developed to ensure efficient and safe spray application in orchards according to actual needs and with respect to the environment. The system consists of three components: 1. Crop Identification System (CIS), 2. Environmentally Dependent Application System (EDAS), and 3. Crop Health Sensor (CHS). A sprayer prototype able to automatically adapt spray and air distribution according to the characteristics of the target, to the level of crop disease and to the environmental conditions is under development.

Non-chemical control of leaf curling midges and sawflies in berries and currants.

The susceptibility of larvae of the leaf curling midge, Dasineura plicotrix, for entomopathogenic nematodes, predatory mites and rove beetles was studied in the laboratory. The results showed that the leaf curling midge larvae were unaffected by the nematodes Heterorhabditis bacteriophora, Steinernema carpocapsoe and S. feltiae. The predatory mite (Hypoaspis aculeifer) and the rove beetle (Atheta coriaria) were very effective in predating the larvae when continuously exposed. However, in a soil substrate the control of larvae was less successful. The vigorous burrowing behaviour of the larvae facilitates their escape from predators. This was enhanced by the formation of a cocoon consisting of soil and sand particles. The effects of the foliar fertilizer magnesium sulphate (bitter salt) were studied on gooseberry sawfty Nematus ribesii. The experiments showed that magnesium sulphate has a good residual action on eggs and neonate larvae. Also, an effect on the egg laying behaviour of the females was observed. The experiments showed that magnesium sulphate has a potential as a control agent for gooseberry sawflies.

Effect of natural windbreaks on drift reduction in orchard spraying.

In the Netherlands windbreaks are commonly grown to protect orchards against wind damage and to improve micro-climate. Natural windbreaks of broad-leaved trees can also reduce the risk of surface water contamination caused by spray drift during orchard spraying. Spray drift from pesticide applications is a major concern in the Netherlands, especially drift into water courses. So far, several drift reducing measures have been accepted by water quality control organisations and the Board for the Authorization of Pesticides (CTB), e.g. presence of a windbreak (i.e. 70% drift reduction at early season and 90% drift reduction at full leaf, respectively before and after first of May). From the experiments it was concluded that the risk of drift contamination is high during the early developmental stages of the growing season. The 70% drift reduction at early season as determined in previous experiments, appears to be valid only for windbreaks with a certain degree of developed leaves. At full leaf stage 80-90% drift reduction by the windbreak was measured. The use of evergreen windbreaks or wind-break species that develop in early season can reduce the risk of drift contamination considerably. Also, the combination of drift reducing methods, such as one-sided spraying of the last tree row and a windbreak is an effective method to reduce spray drift in the Netherlands in early season.

Dead flower buds of pear: effect of tree growth control, and Alternaria alternata as causal agent.

Dead (dormant) flower buds of pear is an important phenomenon in pear production in the Netherlands. Vigourous or unbalanced tree growth and Pseudomonas syringae pv. syringae are mentioned as likely causes of dead flower buds. Several tree growth control treatments including ethephon. Regalis (Prohexadione-Ca) and root pruning were evaluated. Regalis increased disease incidence. The plant stimulant (foliar fertilizer) Resistim (potassium phosphonate) reduced disease incidence. Pseudomonas syringae pv. syringae was occasionally isolated from diseased flower buds. However, Alternaria alternata was nearly always isolated from diseased buds. Indicating a strong relation between this fungus and dead flower buds of pear.

The quality improvement ratio: a method to identify changes in screening rates.

BACKGROUND: Because many managed care organizations are using HEDIS (Health Plan Employer Data and Information Set) and other measurement sets for their report cards, these measurements are also used in improvement projects to show changes over time. One analytic strategy is to compare measurements between one period and another after an intervention has been made. Such an analysis, which is termed here the "conventional" or "two-group analysis" and which would use either a Chi-square test or Fisher's exact test, entails three problems. The conventional analysis is not statistically valid because there are members in common in the two groups; population changes can affect the conventional analysis and confound the identification of any change with time; and members who do not change their behavior obscure the changes that are occurring in the conventional analysis. METHODS: The Quality Improvement Ratio (QuIR) does not suffer from those limitations; it is calculated only from members who change status. For example, in evaluating the effectiveness of an intervention to improve preventive health screening, the QuIR is calculated only from members becoming screened in the second period after being unscreened in the first period, or vice versa. The QuIR is the ratio of the number of members becoming screened in the second period divided by the number becoming unscreened. Methods to test the statistical significance of the QuIR are based on the standard test for paired binary data, McNemar's test. CONCLUSION: Whereas the conventional approach addresses whether there are differences in rates between periods, and analysis using the QuIR focuses directly on whether the rates are different because of an intervention.

Cutaneous melanoma mortality among the socioeconomically disadvantaged in Massachusetts.

OBJECTIVES: To identify groups for melanoma prevention and early detection programs, this study explored the hypothesis that survival with cutaneous melanoma is disproportionately lower for persons of lower socioeconomic status. METHODS: Massachusetts Cancer Registry and Registry of Vital Records and Statistics data (1982 through 1987) on 3288 incident cases and 1023 deaths from cutaneous melanoma were analyzed. Mortality/incidence ratios were calculated and compared, predictors of late stage disease were examined with logistic regression analysis, and a proportional hazards regression analysis that used death registration as the outcome measure for incident cases was performed. RESULTS: Lower socioeconomic status was associated with a higher mortality/incidence ratio after adjustment for age and sex. For education, the mortality/incidence ratio was 0.37 in the lower group vs 0.25 in the higher group (rate ratio = 1.48, 95% confidence interval [CI] = 1.08, 2.03). Late stage disease was independently associated with lower income (rate ratio for lowest vs highest tertile = 1.64, 95% CI = 1.20, 2.25), and melanoma mortality among case patients was associated with lower education (rate ratio = 1.52, 95% CI = 1.09, 213). CONCLUSIONS: Melanoma patients of lower socioeconomic status may be more likely to die from their melanoma than patients of higher socioeconomic status. Low- SES communities may be appropriate intervention targets.

The association of payer with utilization of cardiac procedures in Massachusetts.

To investigate the importance of the payer in the utilization of in-hospital cardiac procedures, we examined the care of 37,994 patients with Medicaid, private insurance, or no insurance who were admitted to Massachusetts hospitals in 1985 with circulatory disorders or chest pain. Using logistic regression to control for demographic, clinical, and hospital factors, we found that the odds that privately insured patients received angiography were 80% higher than uninsured patients; the odds were 40% higher for bypass grafting and 28% higher for angioplasty. Medicaid patients experienced odds similar to those of uninsured patients for receiving angiography and bypass, but had 48% lower odds of receiving angioplasty. In addition, the odds for Medicaid patients were lower than for privately insured patients for all three cardiac procedures. These findings suggest that insurance status is associated with the utilization of cardiac procedures. Future studies should determine the implications these findings have for appropriateness and outcome and whether interventions might improve care.

KIE: This study evaluated the effect of insurance status on the utilization of three widely used and expensive cardiac procedures: coronary angiography, bypass grafting, and angioplasty. Data were obtained from records for all patients with circulatory disorders who were discharged from nonfederal acute care hospitals in Massachusetts during 1985. Analysis of the data revealed that unadjusted procedure rates for privately insured patients were approximately twice the rates for Medicaid and uninsured patients. The latter two groups of cardiac patients underwent procedures at about the same rate. Wenneker, et al. discuss possible reasons for the differences in utilization of cardiac procedures among the three groups of patients. They conclude that their findings raise serious questions about the quality of care for patients with heart disease in the context of payer status, and that further study of the issue is needed.

Racial inequalities in the use of procedures for patients with ischemic heart disease in Massachusetts.

To examine interracial differences in the utilization of coronary angiography, coronary artery bypass grafting, and coronary angioplasty for white and black patients, we examined all admissions for circulatory diseases or chest pain to Massachusetts hospitals in 1985. After controlling for age, sex, payer, income, primary diagnoses, and the number of secondary diagnoses, whites underwent significantly more angiography and coronary artery bypass grafting procedures. Whites also underwent more angioplasty procedures, but the difference was not statistically significant. Although utilization differences may reflect patient preference or different levels of disease severity and socioeconomic status not adequately accounted for, this study suggests that substantial racial inequalities exist in the use of procedures for patients hospitalized with coronary heart disease.