Edgecumbe update

20 November 2014

KVH staff visited Edgecumbe orchards this week to meet with growers and discuss Psa-V progression on orchards in the region this year.

Like other regions, spring has generally been cool, wet and windy in Edgecumbe. Two hail events have also occurred, with the most recent last Thursday coming just before pollination of Hayward. These conditions have been challenging.

Overall, more comprehensive spray programmes have been adopted by most growers in the region. Both KeyStrepto™ and Actigard™ have been widely used in conjunction with copper on a regular basis.

On Gold3 blocks visited, expression of Psa-V symptoms was still occurring with cane dieback and some whole cane collapse seen on more challenged sites. Older, apparently healed cankers were also active on some plants. One block which had young Gold3 plants with scions inadvertently girdled last February, was showing die-back and red exudate around the girdle site.

In contrast, girdles correctly applied to mature stumps remained clear of symptoms. This reinforced the message of care needed when girdling young plants and particularly in high Psa-V risk environments. As expected, levels of symptoms varied between blocks with disease expression appearing worse on cooler or stressed sites. All Gold3 growers in the area are advised to continue actively monitoring and cutting out symptoms to reduce the spread of the disease.

The extent of symptoms on Hayward blocks was quite variable. Growers commented that signs of leaf spotting and bud browning had begun to appear over the past month and in some blocks rapid acceleration of leaf-spot had been seen in the past week after a period of wet windy weather. For some growers there is concern about the potential impact of Psa-V on pollination and fruit set. Artificial pollination will be used as a tool to mitigate risk.

One Hayward site visited highlighted the value of a comprehensive spray programme. Control rows (with no sprays applied) showed severe leaf spotting and significant loss of female flower-buds, while adjacent rows were relatively symptom free and carried good cop loads. Three applications of KeyStrepto™ and four coppers had been applied since bud-break.

  • Click here to view a comparison between side-by-side Hayward rows—one that received a comprehensive spray programme, and adjacent vines that did not receive any spray protection over spring.

A G14 block visited showed increasing signs of bud rot despite an active protective spray programme.

Overall, Psa-V continues to make growing in this region a challenge. However, growers in general were quietly confident of a better fruit set than was achieved in 2013. Several Psa-V related trials continue within the Edgecumbe area.