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Raspberry Bushy Dwarf Info: Learn About Raspberry Bushy Dwarf Virus

Raspberry Bushy Dwarf Info: Learn About Raspberry Bushy Dwarf Virus


By: Kristi Waterworth

Gardeners growing raspberry brambles spend several seasons waiting for their first real harvest, all the while tending their plants carefully. When those raspberries finally start to flower and fruit, the disappointment is palpable when fruits are sub par. The same goes for older plants that once produced big, healthy fruits but now seem to halfheartedly set fruits that aren’t fit for consumption. Let’s learn more about treating plants with RBDV.

What is RBDV (Raspberry Bushy Dwarf Virus)?

If you’re seeking raspberry bushy dwarf info, you’re not alone. Many raspberry growers are shocked by the signs of raspberry bushy dwarf disease when they first appear, especially the fruit symptoms. Instead of setting healthy fruits, raspberries infected with raspberry bushy dwarf virus have fruits that are smaller than normal or crumble at harvest time. Yellow ring spots may appear briefly in the spring on expanding leaves, but soon disappear, making detection difficult if you’re not in the brambles frequently.

Because raspberry bushy dwarf virus is primarily pollen-transmitted, it may be difficult to know if your raspberries are infected before the fruit signs of raspberry bushy dwarf disease appear. If nearby wild raspberries are infected with RBDV, they can transmit it to your domesticated raspberries during pollination, leading to system-wide infection as the virus makes its way through your plants.

Treating Plants with RBDV

Once a raspberry plant is showing signs of raspberry bushy dwarf virus, it’s too late to treat them and removal is the only option to stop the spread of this disease. Before you replace your raspberries though, scour the area for wild raspberries and destroy them. This may not protect your new raspberries completely, since pollen can travel long distances, but it will increase your chances of staying disease-free.

You can also transmit RBDV to uninfected plants on unsterilized tools, so make sure to thoroughly clean your equipment before using it to plant certified nursery stock. When shopping for new raspberry plants, watch for the varieties Esta and Heritage; they are believed to be resistant to raspberry bushy dwarf virus.

Dagger nematodes have also been implicated in the spread of RBDV between raspberry plantings, so choosing a completely new site for your new raspberries is recommended as a protective measure since these nematodes can be difficult to eradicate.

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Pest & Disease Identification on Blackberry Plants

Blackberries (rubus) are called “brambles” for good reason: Their canes grow in thorny jumbles. Home gardeners grow trailing blackberries on trellises or bushy upright varieties all over the country, but most commercial blackberries grow in the Pacific Northwest where the climate suits them best. Each berry is actually an “aggregate” of smaller fruits called “drupelets,” each containing a seed. Several fungus diseases and pests affect blackberries.


Fungal Diseases

Verticillium wilt and amellaria root rot are caused by soil fungi, and phytophthora root rot is caused by a funguslike organism. Verticillium wilt and phytophthora root rot cause leaves to turn yellow and wilt before canes start dying, and plants affected with amellaria root rot die suddenly. Anthracnose and cane blight fungi breed in canes and survive through the winter. They can infect pruning wounds and other damage sites on raspberry canes. Downy mildew arises from infected roots and shoots, and it, along with powdery mildew, affects raspberry plant leaves. Powdery mildew also affects raspberry plant flowers and fruits. Purple blotch is a fungal disease that lives on and affects raspberry canes.


Performance and Description

‘Wakefield’ was tested and evaluated as an advanced selection between the years 1996 to 1998 at PFR Motueka, New Zealand, and in 2009 and 2010 at Enfield Farms Inc., Lynden, WA. In Washington, ‘Wakefield’ was included in a randomized complete block design trial along with three other genotypes (NR18, ‘Meeker’, and ‘Willamette’) and three replicates each of six plants (spacing 70 cm between plants, 3 m between rows), which was planted in May 2008. Percent budbreak during spring [recorded as the percentage of buds broken (0 = none, 10 = all)] and flowering time [recorded as percentage of flowers open (0 = none, 10 = all)] were recorded as scores for each plot. Each six-plant plot was machine-harvested every 2 to 2.5 d between 29 June and 7 Aug. in 2009 and 29 June and 11 Aug. in 2010, and fruit weights were recorded. For each plot, a loess smooth curve of cumulative yield vs. date was interpolated to derive the mid-harvest date (date at which 50% of the final yield had been harvested) and harvest span (number of days over which the middle 95% of the crop was picked).

Firmness measurements (mean of 25 fruit × three harvest dates: early, mid, and late) were made using a Firmtech 2 firmness tester (Bioworks Inc., KS) and mean berry weight was recorded. Juice samples were extracted from 25 fruit and three harvest dates using a potato ricer, combined, and were analyzed for total anthocyanin by high-performance liquid chromatography [HPLC (Shimadzu, Portland, OR)] in a manner similar to that described by Connor et al. (2005) and total ellagitannin determined by HPLC was quantified using purified Sanguiin H6 as a standard. Antioxidant capacity was determined by ferric-reducing antioxidant power and total phenolics through the Folin assay using methods similar to those described by Benzei and Strain (1999) and Zhang et al. (2006), respectively. Soluble solids content was recorded using a digital pocket refractometer (PAL-1 Atago, Tokyo, Japan) and for total acidity measurements, 2 mL of berry juice in 40 mL of water was titrated with 0.1 M NaOH to pH 8.2 on an autotitrater (T70 Mettler Toledo, Zurich, Switzerland). Data were analyzed by analysis of variance using R 2.9.0 (R Core Development Team, 2010).

‘Wakefield’ was very well adapted to machine-harvesting because ripe fruit are very easily released from the plant laterals. In addition, very few non-ripe (green) fruit were accidently removed by the machine in comparison with ‘Meeker’ (data not shown). Our results show ‘Wakefield’ fruit were significantly firmer than those of ‘Meeker’ and ‘Willamette’ and had comparable soluble solid contents (Tables 1–4). The ability to machine-harvest firm fruit makes ‘Wakefield’ very suited to production of fruit for IQF markets. ‘Wakefield’ fruit had higher acidity, anthocyanin content, and higher antioxidant capacity than those of ‘Meeker’ (Tables 2 and 4). In 2010, ‘Wakefield’ had higher machine-harvested yield than ‘Willamette’ and ‘Meeker’ and was harvested in a similar or later season than ‘Meeker’ and harvested significantly later than ‘Willamette’ (Table 3).

Mean time of budbreak (score 0 = no buds broken, 10 = all buds broken on 7 Apr. 2009), flowering score (0 = no open flowers, 10 = all flowers open on 8 June 2009), and fruit harvest measurements for first crop 2009 for the red raspberry replicated trial.

Mean fruit chemistry measurements for the first crop 2009 for the red raspberry replicated trial.

Mean time of budbreak (score 0 = no buds broken, 10 = all buds broken on 1 Mar. 2010), flowering score (0 = no open flowers, 10 = all flowers open on 4 June 2010), and fruit harvest measurements for second crop 2010 for the red raspberry replicated trial.

Mean fruit chemistry measurements for second crop 2010 for the red raspberry replicated trial.

Using available pedigree information, we calculated the genetic contribution of R. idaeus, R. strigosus, and R. pileatus to ‘Wakefield’ to be 83.6%, 13.3%, and 3.1%, respectively. We calculated the inbreeding coefficient of ‘Wakefield’ to be zero, indicating that ‘Wakefield’ is not inbred (Fig. 2). However, it should be noted that the pedigrees of all ancestors were not necessarily complete.

Pedigree of ‘Wakefield’ red raspberry, including inbreeding coefficients.

‘Wakefield’ plants are semi-spineless and carry the Ss gene (Lewis, 1939) with a moderate number of small spines near the base and fewer on upper parts of the canes. ‘Wakefield’ canes are pubescent (H gene) (Jennings and Brydon, 1989).

Measurements from our replicated trial on ‘Wakefield’ show that it has significant advantages over the current commercial cultivars Meeker and Willamette in terms of fruit yield, fruit quality, and disease resistance.

The new cultivar was first asexually propagated in 1994 in New Zealand, being reproduced by root cuttings, and since 2005, ‘Wakefield’ has been propagated by tissue culture. Currently ‘Wakefield’ is propagated by tissue culture methods because it produces relatively low numbers of adventitious root shoots in a nursery compared with cultivars such as ‘Meeker’ and ‘Willamette’. The resulting plants propagate true to type, demonstrating that the characteristics of the new cultivar are stable and can be transmitted without change through succeeding generations of multiplication.


Highlights in European Plant Biotechnology Research and Technology Transfer

Abstract

Mycosphaerella graminicola is a high host-specific pathogen, causing Septoria tritici leaf blotch of wheat. Histopathological studies suggested the involvement of toxic compounds in the disease. When tested on various substrates and culture conditions, M. graminicola expressed the highest toxicity on M- 1-D in shaken culture (150 rpm) incubated at 22 °C in the dark for two weeks. In M-l-D liquid culture M. graminicola produced phytotoxic acidic compounds with high water affinity. The culture filtrates were tested in different bioassays to assess their phytotoxicity. No correlation was observed when the phytotoxic activity of 24 different strains of M. graminicola was evaluated in relation to their virulence on susceptible and resistant wheat cultivars. This analysis indicates that phytotoxic metabolites of M. graminicola are no determinants of virulence although they may contribute to the extent of disease development


Insects

The University of Arkansas examines a number of insects that affect blackberries. Aphids, leafrollers and thrips may rise in clouds from plants and leave shrunken and deformed leaves in their wakes. The rednecked cane borer creates galls, splits in bark and holes in leaves on primocanes in April through June. Blackberry psyllids attack terminal leaves on the outside of the bramble as flower buds swell. Strawberry clippers or strawberry bud clippers eat around the base of flower buds. Deformed fruit and poor drupelet development indicate the presence of stink bugs or blackberry midges. The green June beetle and Japanese beetle both eat leaves and developing fruit in June by July, they eat only ripe fruit. The raspberry crown borer attacks the roots in the crown of the plant canes wilt and the tops bend over in a “shepherd’s crook” shape.

  • The University of Arkansas examines a number of insects that affect blackberries.
  • The raspberry crown borer attacks the roots in the crown of the plant canes wilt and the tops bend over in a “shepherd’s crook” shape.

Bugs on raspberries friend or foe??

I have these very tiny black & white bugs on my raspberry bush. The plant looks pretty healthy but it's not producing much fruit at all. Could these little bugs be the cause? If so what are they & how do I get rid if them.
Thanks!

No and no.
It looks like it could be a Twenty Spotted Lady Beetle. Psyllobora vigintimaculata
I read they eat mildew spores. I would think that is a good thing in the garden.
I would look for cultural causes. What type of raspberries and how old are the canes?

Hi, thanks for your response! The little bugs are multiplying fast! So it's good to know they're more beneficial than harmful. The raspberry bush is new, I just planted it this year. The tag that came with the plant refers to it as Rubus Hybrid: 'Heritage' Red Raspberry. It is apparently supposed to bear fruit from July to September but like I said not a whole lot happening yet. I've had maybe 6 raspberries in total so far :( I have been fertilizing it as well & it looks really healthy just no fruit.

Thanks again for your response. If you have any suggestions/recommendations I'd love to hear them :)


Watch the video: Bumble Bee enjoying my raspberry bush ;