The pictures below are of mis-shapen fruit from two commercial blackberry plantings (one cultivar in each) which have a significant proportion of their fruit affected as shown in the two pictures below.  Both cultivars have many fruit which are incompletely pollinated, in other words, the druplets at the tips of the fruit are not filling and forming.  The result of this is that the fruit has a distorted appearance and a reduced saleability in a fresh market venue.  Nevertheless, since in blackberry the receptacle is harvested together with the fruit there is some structure and stability so the fruit will not be crumbly as would the case be in raspberry.

One would think that the blackberry flower, composed of a succulent receptacle with so many pistils on top of it surrounded by yet more whorls of stamens would not have difficulty pollinating, but it does on occasion.  Along with the pollen, these various structures of the flower are viable for only for short periods of time, and if anything impedes with their intended function during this time, for example wind, rain, excessive heat or lack of pollinators, active pollen will not adhere to the stigma.  The end result of this interference of normal flower function is that the druplet in question will not “make” properly, and the fruit will be mis-shapen.

Indeed, it is common to find pollination problems to be often manifested across one cohort of fruit, i.e. of one size since all the flowers of that cohort were exposed at the same time.  The situation today was that fruit of different ages however were affected, which clouded the case somewhat.   However, thinking back and double checking the records of CIMIS Station #111, we see that there were several (as opposed to one) rainstorms in March and especially April which could have wrecked havoc on many cohorts of flowers over time.  The determination was made that it was this number of unfavorable weather events that caused this malformation of the fruit.  We would not expect to have much fruit malformation past those events, and certainly not going forward.

The pictures below are of a species of sap feeding beetles (Family Nitidulidae) found in one section of a local strawberry field.  This case of these insects is pretty interesting simply because they are so uncommon to find in Watsonville.

Conditions of discovery are the following.  The location is a beautiful strawberry field full of big fruit, bordered by apples and blackberries. It is only the five or six rows bordering the apples and blackberries that have these sap beetles.

The beetles occur in groups of four to six mostly on the undersides of the fruit and excavate holes there, in which several beetles at a time gather.  One characteristic of infested fruits is that they are quite mature or even over ripe, which is in keeping with the host and feeding preferences of this family of insects.

As one can see from the first two photos below, distinguishing characteristics of sap beetles are the club shaped antennae, and shortened elytra exposing in this case three abdominal segments.

The solution to this problem is quite simple.  One would want to remove and discard affected fruit from the field, and if very concerned, one could even do a cover spray with an insecticide of the infested rows- it's really not necessary to do the whole field.  Additionally, I have a feeling some of this is related to the moist weather we have had over the past few weeks, so as we move into the drier summer period it's quite probable that these insects will simply go away on their own.

I mention the use of pesticide for management of sap beetles in this article.  Before using these products, check with your local Agricultural Commissioner's Office and consult the product label for current status of product registration, restrictions, and use information.

This comes up a couple of times every year so it is worth reviewing and certainly adds value to our catalogue of plant disorders on these berry blogs.

The following plant sample of a proprietary variety was received 4/24/2012.  One can see immediately that the leaves are chlorotic and burnt at the margins and in some cases (photo 2 below) newer leaves are somewhat deformed as well.  Most often one will encounter a pink tint to many of the leaves.

The situation in the field was as follows, a mixture of Round Up (glyphosate) and Shark (carfentrazone) was applied to the field to control weeds one month prior to planting.  According to weed scientist Steve Fennimore,  the Shark does not linger in the soil for any significant period of time, actually around three hours tops.  On the other hand, Round Up can linger for a while, maybe even longer than a month especially in a sandy soil in which it is not adsorbed to fine soil particles as it would in a clay.

The solution to this predicament, and indeed in all cases of Round Up toxicity, is to let the plant grow out of it.  Raspberries have substantial stores of carbohydrates to draw on and can usually overcome the temporary inhibition of photosynthesis caused by mild herbicide damage such as the case presented here.

There are several herbicides mentioned in this article.  Before using any herbicides, check with your local Agricultural Commissioner's Office and consult product labels for current status of product registration, restrictions, and use information.

Here is another example of orange rust, which are caused by two fungi, Arthuriomyces and Gymnoconia, the two of which are distinguished by the shape of their spores and life cycle length.  To re-iterate, growth of orange rust is strictly on blackberry and is favored by cooler temperatures and high humidity, but I have yet to see an infection of this rust explode across the landscape no matter what the conditions are.  Instead, several plants around a single locus will show infection at one time and the advance of the disease, if not addressed, is measured in years rather than days or weeks. 

Orange rust is distinguished by the intensity of its orange color and the sharp outlines of the infected area.  Usually one can see the spores by rubbing or brushing up against the leaves.

Probably the most important point about managing orange rust in the field is that it is systemic and cannot be controlled by any fungicide we have labeled in blackberries.  Leaving plants alone or trying to spray one’s way out of it will end in tears.  Orange rust MUST be removed by hand, that is to say the whole infected plant dug out with a shovel.  It is best to remove plants directly adjacent to the infected area as well, since they are quite likely infected but not yet showing the symptoms.  Take care to remove the whole plant, including the roots down to at least 12 inches.  Plants should be bagged at the point of removal and disposed of properly.  Personnel removing the plants should use clothing which can be disposed of or washed quite soon after working with the infected plants so as not to continue to spread spores across the blackberry field over the course of the remaining workday.

One last point, graphically illustrated in the last picture, is that groundsel in blackberry fields gets a type of rust also, but this is not the same rust the orange rust occurring on blackberry and is rather a species of Puccinia.  Rusts tend to pretty specific to their hosts, so removing groundsel with the goal of reducing the rust pressure on blackberries will not work.

Yet another hat tip to the PCA and grower for letting me know about this one.