Preplant soil-incorporated compost, mycorrhyzal innoculation (MI) at planting, and the combination of the two were tested for growth and yield increase of `Honeycrisp' apple trees on two rootstocks, M.26 and G.16. Compost was added at a rate of 0.51 m3 per tree. Within each main plot of compost or no compost were planted four trees with two on each rootstock. Noncompost plots were fertilized with N in year 1 and N, K, and Mg in year 4. The MI had no effect on growth until the third and fourth years after planting when annual trunk growth and tree height were greater than the untreated control. Compost increased trunk growth in the third and fourth years, but decreased growth in the fourth year when combined with MI. G.16 had greater trunk growth and tree height than M.26 in years 3 and 4. Fruiting was delayed by pruning at planting, so trees fruited for the first time in the fourth year. Bloom and yield were not increased by MI. There was more bloom and yield on G.16 than on M.26. Yield of G.16 was increased by compost from 0.08 to 1.2 kg/tree. The combination of MI and compost increased bloom compared to the control, but not yield, which was 0.3 kg/tree. Compost increased bloom but not yield of M.26, since this rootstock had low yield when planted in compost, 0.2 kg/tree, and none when planted without compost.
Renae E. Moran
The goal of this project was to evaluate the effectiveness of aminoethoxyvinylglycine (AVG) for increasing effectiveness of 1-methylcyclopropene (1-MCP) for maintaining firmness and preventing scald in `McIntosh' and `Cortland' apples (Malus ×domestica). AVG and 1-MCP used together maintained `McIntosh' apple firmness more than 1-MCP used alone after 120 or 200 days of controlled-atmosphere (CA) storage. AVG and 1-MCP can be used to maintain firmness of `McIntosh' when internal ethylene concentration (IEC) at harvest is as high as 240 μL·L-1, but CA storage life is limited to 4 months. AVG was not effective at increasing efficacy of 1-MCP on `Cortland' when IEC at harvest was not significantly different between AVG-treated and untreated fruit and IEC was less than 2 μL·L-1. AVG increased efficacy of 1-MCP on `Cortland' when IEC was 36 μL·L-1 in untreated fruit compared to undetectable in AVG treated fruit. 1-MCP prevented scald of `Cortland' in 1 year and reduced it to 5% or less in another year when fruit were stored 120 days. 1-MCP reduced `Cortland' scald to 34% or less after 200 days of storage.
Renae E. Moran
In 2004, prestorage delays and CA storage were compared for occurrence of disorders. Fruit were harvested at a starch index of 5.9. Fruit were exposed to either a 2- or 5-day prestorage delay at 17 °C; or placed immediately into cold storage (control) at 0.5 °C. An additional treatment was CA storage at 2.5 °C. In February, occurrence of soft scald, soggy breakdown, and bitter pit were measured on 40 fruit per replication. Fruit were from `Honeycrisp'/M.26 trees planted in 1994. Treatments were replicated five times with four trees in each replication. Soft scald was very severe in this year, with 84% of control fruit being affected. Two-day prestorage delay reduced it to 48% and 5-day delay to 21%. Soggy breakdown was also severe with 14% of the fruit being affected. Two- and 5-day delays had no effect on occurrence of soggy breakdown, but CA storage increased it to 65%. Bitter pit was very rare and not affected by any of the treatments. These results demonstrate that in severe cases, shorter prestorage delay is not effective in preventing soft scald or soggy breakdown.
Renae E. Moran and Curt Rom.
Greenhouse grown `Lawspur Rome'/M.111 trained to single shoots were given the following shade (73%) treatments: 1) sun-all-day (control), 2) shade in the morning (am-shade), 3) shade in the afternoon (pm-shade) and 4) shade-all-day. All shade treatments increased shoot length and decreased dry weight/leaf area (DW/LA). Shade-all-day increased leaf no., LA/leaf and shoot dia. DW partitioning to leaves in shade-all-day was 19% greater than control and to roots was 34% less than control. Pn of am-shade did not increase in the afternoon when PFD was maximal. Saturated net photosynthesis (Pn) was 72% of control in am-shade, 84% of control in pm-shade and 62% in shade-all-day. Shade reduced Pn by 40% of control.
Renae E. Moran and Patricia McManus
1-Methylcyclopropene (1-MCP) maintained firmness of `Macoun' apple (Malus ×domestica Borkh.) above 50 N after 90 to 100 days regular air storage when harvested at a starch index of 2.7 to 3.5, and after 50 days when harvested at a starch index past 4.0. Softening of `Macoun' was slowed by 1-MCP in both preclimacteric and climacteric fruit, but for a shorter duration in climacteric fruit. 1-MCP reduced but did not eliminate the occurrence of senescent breakdown. The effect of 1-MCP on coreline browning was inconsistent, reducing its occurrence in 2002 and 2003, but increasing its occurrence in 2001 when fruit were harvested at an advanced maturity.
Renae E. Moran and James R. Schupp
'Macoun'/Budagovsky 9 apple (Malus ×domestica Borkh.) trees were planted in May 1998 in one of four preplant treatments that were soil incorporation of: 1) control, no phosphorus (P); 2) 90 g P per tree; 3) 128 kg compost per tree; and 4) 90 g P and 128 kg compost per tree. Preplant addition of P had no effect on soil organic matter, P, magnesium (Mg), and calcium (Ca) in the first three seasons after planting, but lowered soil potassium (K) in the second season. Foliar nutrients, tree growth and flowering were also not affected by P. The addition of compost increased soil organic matter and P in the first season after planting, and pH, K, Mg, and Ca in the first three seasons. The addition of compost increased foliar nitrogen and K in all three seasons, and decreased foliar Mg in the first season. Compost incorporation increased shoot length in the first season, trunk cross-sectional area in the first two seasons, tree height and the number of growing points in third season, and flowering in the third and fourth seasons. Compost addition was more effective than P fertilization for increasing tree growth during the establishment years.
Christina S. Howard, Renae Moran, and David Handley
The strawberry bud weevil (Anthonomus signatus), “clipper,” is an invasive pest to northeastern U.S. strawberry and raspberry crops. Strawberry is the primary host of clipper, but it has been observed damaging raspberry crops as well. The first objective for this research is to determine the importance of clipper as a pest on raspberries in the northeastern U.S. Raspberry plantings were scouted weekly on 13 grower-cooperator farms in Maine during the late spring and early Summer 2005 for the adult insects and bud injury (clipped or not). 10 canes from each site were then collected and the number of total buds and clipped buds were taken. This data will be correlated with the bud injury data to determine interrelationships between clipper populations and bud injury levels on different varieties of raspberries. The first year of this research has determined that clipper is a pest of raspberry in the northeastern U.S. Up to 55% clipper damage was found on raspberry plants in 2004 and up to 22% clipper damage was found in 2005. The other objective for this research is to develop integrated pest management (IPM) strategies for clipper on raspberry crops in the northeastern U.S. While scouting the farms this past summer, some different scouting techniques were tested for their efficiency and effectiveness at predicting the population levels of clipper on the crop. The scouting method of white sticky traps were hung in the field and provided the most accurate method of scouting for clipper in the field. In addition to this research, the importance of clipper as a pest of raspberries was tested using greenhouse-grown plants. They were analyzed for the ability of raspberry fruit yield to compensate for the loss of flower buds due to clipper damage. The research showed that plants with any clipped buds yielded significantly lower and the mean number of berries is significantly lower than the control plants with no clipped buds. The results also showed that the mean berry size was highest if there were no primaries clipped and significantly lower if primaries or secondaries were clipped concluding that there is little or no compensation in Killarney red raspberries when buds are clipped. This is a thesis project in progress with one more season of data to collect. Concluding the research, this work should improve grower awareness of clipper as a pest of raspberries and provide an IPM program to manage clipper on raspberries in the Northeast.
Renae E. Moran and James R. Schupp
'Macoun'/B.9 apple (Malus ×domestica Borkh.) trees were planted in May 1998 in ± compost or ± monoammonium phosphate (MAP) for a total of four preplant treatments: 1) 90 g phosphorus (P) per tree, 2) 128 kg compost per tree, 3) 90 g P and 128 kg compost per tree, and 4) and an untreated control. MAP did not increase tree growth or yield in any year of the study. Compost increased canopy width into the sixth year after planting, and increased tree height and trunk cross-sectional area (TCA) into the seventh year. Annual yield was increased by compost in the fifth and seventh years, but not fourth or sixth year after planting. Compost increased cumulative yield in the sixth and seventh years.
Renae E. Moran and Stephen M. Southwick
Secondary bloom provides fireblight infection sites in pears (Pyrus communis L.) growing in the western U.S. Five types of secondary bloom occur in `Bartlett', and one of these, Type V, occurs mainly as a result of pruning. We examined the effect of pruning dates (Feb. to Sept. 1999), shoot age ranging from 1 to 4 years old, and type of pruning cut (i.e., heading, stubbing, or thinning) on Type V secondary bloom. Pruning date was a significant factor determining whether Type V would occur. There was a greater chance for Type V to occur from pruning in February or March than for pruning from May through September. There was an increase in Type V with increase in shoot age when pruning 11 Feb., 17 Mar., 14 May, or 11 Aug. There was no shoot age effect when pruning 18 June or 30 Sept. Type of pruning cut affected the number of Type V that occurred when pruning 14 May, 18 June, or 11 Aug., but the effect of type of pruning cut was inconsistent between these dates. There was no effect of type of pruning cut when pruning 11 Feb., 17 Mar., or 30 Sept. These results indicate that summer or postharvest pruning may reduce the number of Type V secondary bloom, particularly on shoots older than one year. This information can be used to develop a pruning strategy that reduces the number of Type V secondary bloom and potentially the number of fireblight infection sites.
Renae E. Moran and Curt R. Rom
The relationship of variability in flowering and fruiting habit to canopy position and changing diurnal light and photosynthetic pattern was examined in 7 mature spur-type `Red Delicious'/MM106 apple trees. A .5×.5m column was placed in the north, south, east and west sections of tree canopies. Columns were subdivided by height with 3 study areas located at .25-.5m, 1.0-1.25m and 1.75-2.0m from the top of the canopy. In each, section, flowering index, fruit set, individual fruit weight and size, skin coloration, fruit soluble solids content, spur leaf area and spur bud diameter were determined. Photosynthetically active radiation and photosynthesis were measured from bloom through harvest correlated with variability in flowering, fruiting, spur quality and distribution of growth.