Carolina redroot is a common weed of New Jersey cranberry beds that competes with crops for nutritional resources but also serves as a food source for waterfowl. Greenhouse studies were conducted in 2017 in Chatsworth, NJ, to determine control of Carolina redroot aboveground vegetation and rhizome production with 10 herbicide active ingredients. Herbicides were applied as a single application on 10- to 15-cm-tall plants. Diquat at 560 g ai ha−1 and mesotrione at 280 or 560 g ai ha−1 controlled more than 90% of emerged shoots at 63 d after treatment (DAT). Aboveground vegetation control at 63 DAT reached 87% with 2,4-D and flumioxazin but was limited with glyphosate, not exceeding 40%. Mesotrione at 560 g ai ha−1 provided 98% control of roots and rhizomes (root/rhizome) at 63 DAT, a 10% increase compared with 280 g ai ha−1; and 2,4-D (90%), glyphosate (87%), diquat (86%), and flumioxazin (85%) also showed excellent root/rhizome control. The greatest reduction of plant biomass compared with the nontreated check (UNT) was noted with 2,4-D, mesotrione at 280 g ai ha−1 and 560 g ai ha−1, and diquat, with decreases from 73% to 80% for shoots and from 82% to 88% for roots/rhizomes. Glyphosate had less impact on shoot biomass reduction (−56%) but similar effect on root/rhizome dry weight (−79%) compared with 2,4-D, mesotrione, and diquat. Flumioxazin and fomesafen significantly reduced root/rhizome biomass by 78% and 72%, respectively. Concurrently, 2,4-D, flumioxazin, fomesafen, and diquat reduced the number of secondary shoots 70% to 90% compared with the UNT, whereas glyphosate and mesotrione completely inhibited emergence of new shoots. These data suggest that mesotrione applied POST provides excellent control of Carolina redroot. Future research should evaluate field applications of mesotrione in early summer when Carolina redroot regrowth occurs following the dissipation of PRE herbicide activity.

Dodder seeds are physically dormant because of hard seed coats and do not readily germinate without scarification. Reliable methods of scarification for small lots of dodder seed are needed to facilitate laboratory, greenhouse, and field research projects. Dodder seed was scarified for varying times using a handheld rotary tool at the 10,000 rpm setting with a conical grinding-stone bit attached. Percentage of germination and weight change of seeds were assessed using scarification times between 0 and 4 min at 0.5-min increments. Mean seed weight loss and mean number of germinated seeds increased quadratically as scarification time increased. Scarifying for 2.5 min was judged the shortest time with maximal germination. Another study evaluated the effect of seed number (100 to 400 seeds sample−1) on the efficacy of rotary tool scarification when scarification time was held constant at 2.5 min. Percentage of germination decreased linearly as seed batch size increased. The handheld rotary tool provides consistent and repeatable scarification of dodder seed with germination rates greater than 80%.

Dewberry is a weed found on cranberry bogs that spreads quickly, causes high yield loss, and has no effective management strategy. Finding options to manage damaging perennial weeds in a perennial crop system, such as cranberry, is key to long-term industry sustainability. This study presents preliminary data on the use of flame cultivation (FC) in cranberry weed management. Utilizing weeds transplanted from commercial cranberry farms to a prepared area at the UMass Cranberry Station, we evaluated three handheld propane-fueled FC instruments: infrared torch, open flame torch, and an infrared torch with a spike. A single, midsummer exposure (zero, low, medium, or high duration) with each FC was tested. The industry standard of using a single wipe application of an herbicide solution (111 g L−1 ae glyphosate, isopropylamine salt) was also included in the evaluation. Dewberry shoot, root, and total biomass decreased linearly as exposure increased; the effect of FC tool type was not significant. Data indicated that, regardless of the specific torch utilized, spot treatment with FC reduced dewberry biomass. The results of this exploratory study suggest that FC may offer an alternative technique for managing woody weeds and that further research is warranted.

Field studies were conducted in 2009 and 2010 on established commercial cranberry farms in southeastern Massachusetts to evaluate cranberry vine injury and yield with two rates of dichlobenil (1.8 and 2.7 kg ai ha−1) applied at various growth stages starting in mid-May. Four varieties were evaluated: ‘Ben Lear', ‘Early Black', ‘Howes', and ‘Stevens'. Ben Lear vines exhibited leaf-stress symptoms in both years, and Howes and Stevens vines had leaf symptoms in 1 yr. Data indicated that applications made during periods of flower-part development and growth (jewel through bloom) had the highest injury ratings. Growth stage affected injury ratings by variety and dichlobenil rate in 1 out of 2 yr. In all cases, leaf symptoms abated by the end of the season. No effect on yield (wt of fruit per unit area) was detected for any treatment combination on any variety in either year. Data from the present study support pursuit of future studies and can guide management decisions for dodder control to a limited extent. Longer studies are needed to fully evaluate repeated, annual applications of dichlobenil dispensed during periods of rapid growth on cranberry vine development and yield. Further work is also needed to document the practical use of delayed applications of dichlobenil for dodder management.

To address grower concerns that repeated use of dichlobenil could negatively affect cranberry productivity, field studies were conducted at two commercial farms in either high weed density (HW) or low weed density (LW) areas. Data from 4 yr of repeat annual applications of 0, 1.8, and 4.5 kg ai/ha dichlobenil indicated minimal negative impact on cranberry vines. Herbicide application did not affect upright productivity, leaf biomass production, percent fruit set, or other yield parameters adversely; in addition, no improvement in these parameters was noted. Although the interaction of herbicide application with weed density on cranberry root length varied with sampling date, no consistent trend (adverse or positive) was seen. The presence of weeds, rather than herbicide application, was the important determinant of yield. Vines in LW areas produced more marketable fruit and had higher percentage of fruit set than vines growing in HW areas. Repeat annual applications of dichlobenil on commercial cranberry beds may be considered as part of a viable integrated weed management program with no adverse effect on crop growth or yield.