THINKING ABOUT GROWING PISTACHIOS? BEN THOMAS Ben Thomas Consulting

CLIMATE CONSIDERATIONS Winter chill Winter chill needed to break tree dormancy and promote good, even and timely bud break. Dynamic chill portions. Newsletters provided by PGA Dormant winter oil applications Heat requirements Growth rate of plants depends on heat Pistachios require sufficient heat to drive kernel development. Rain during harvest Increases risk of disease (e.g. anthracnose in 2011) Delays harvest which can lead to more shell staining and downgrading of product Frost Pistachios, like other tree crops, are sensitive to frost close to or shortly after bud burst Slide 2

DYNAMIC CHILL PORTIONS - MILDURA Slide 3

POTENTIAL FROST DAYS Slide 5

SOIL Soil requirements Pistachios often planted on less favourable soils Like other tree crops, perform better with favourable soil conditions (i.e. neutral ph, >60cm potential root depth above restricting soil layers) Soil information Good general information available online. Use soil surveyor to provide detailed soils information which can be used to design irrigation systems etc. Poor drainage and waterlogging are key considerations Amelioration and preplant fertilisers Preplant soil analyses will indicate whether soil ameliorants (lime, gypsum, organic matter) and/or preplant fertilisers are needed. Slide 6

WATER Source of water River or bore Pipeline and pumping costs Water quality Irrigation requirements Theoretical water requirements based on evaporation and rainfall commonly 12-13ML/ha Pistachios have a reputation of being drought tolerant but require considerable irrigation for optimal performance. Slide 7

ROOTSTOCKS AND VARIETIES Rootstocks Most recent Australian plantings have used Pioneer Gold I (PG I) or UC Berkeley I (UCB I) rootstocks. PG I is Pistacia integerrima whilst UCB I is a hybrid rootstock (P. atlantica x. P. integerrima) Pistacia terebinthus and P. atlantica are older rootstocks and were commonly planted in the early days of the Australian industry The rootstocks vary in vigour, cold tolerance, susceptibility to diseases, salinity tolerance, micronutrient uptake efficiency. Experience in Australia with UCB I is limited but it appears to be more vigorous than PG I. Varieties Sirora was bred for Australian conditions and is the main variety grown. Kerman is the main variety grown in California. Slide 8

OTHER CONSIDERATIONS Juvenility Pistachio trees have a long juvenile period (6-8 years) before they start producing fruit Male tree percentages Pistachio is dioecious (meaning two houses ) and so male flowers are borne on one tree and female flowers on another Pistachio is wind pollinated and so male trees are interspersed through the orchard Initial plantings in Australia had high male percentages (8-12%) but given the amount of pollen produced, more recent plantings use 4% male trees Planting density Many growers are now looking at denser plantings to improve early production especially given the long juvenile period. Slide 9

OTHER CONSIDERATIONS Pest and disease Pistachio in Australia have few pests. Key diseases are anthracnose, Xanthomonas and Botryosphaeria shoot and panicle blight. Biennial cropping Pistachios will biennial crop meaning alternate on-crop and off-crop seasons. Hulling and processing Pistachios need to be hulled as soon as possible following harvest to maximise quality. There is one major processor in Australia based at Robinvale. Slide 10

FIRST YEAR Good establishment Tree losses kept to a minimum. Keep a close watch on irrigation. Solid but not excessive growth Key aim is having a rootstock that can be budded in January. Ideal rootstock for budding is about pencil to little finger thickness. Allow scion to grow for the rest of the season. Key management issues Water, wind and weeds! Windbreaks permanent or temporary? Cover cropping Staking options Tree guards Nutrition Slide 11

FIRST YEAR PLANTING AND ESTABLISHMENT Slide 12

COVER CROPPING Slide 13

WINDBREAKS Slide 14

FIRST YEAR GROWTH OF NEW BUD Slide 15

FIRST YEAR TRADITIONAL Slide 16

FIRST YEAR MODIFIED CENTRAL LEADER Slide 17

SECOND AND THIRD YEAR Vigour and training SECOND YEAR Traditional training aiming to establish tree framework. Requires multiple training passes to develop primary, secondary and tertiary branches. Modified central leader training Trees at desired height can be headed in winter prior to second growing season. Minimal in-season training. Vigour and training THIRD YEAR Traditional training continue to develop tree framework. Modified central leader training Primary scaffold limbs selected in winter prior to third growing season. Minimal in-season training. Key management issues Water, wind and weeds! Tree guards Rootstock Nutrition Slide 18

SECOND YEAR MODIFIED CENTRAL LEADER Slide 19

SECOND YEAR TRADITIONAL Slide 20

NUTRITION - YOUNG TREES Macronutrients Nitrogen Small and regular feeds. Minimise potential losses of nitrogen via leaching etc. Which forms of fertiliser? Phosphorus Preplant applications Can consider small applications through fertigation in spring Potassium Preplant applications often not necessary Can consider small applications through fertigation in spring More important once trees start cropping Slide 21

NUTRITION YOUNG TREES Micronutrients Zinc Young trees particularly susceptible. Zinc immobile in plants so regular zinc foliar nutrient sprays needed to ensure new growth is treated. Copper Have observed symptoms on young trees in recent seasons. Regular copper chelate foliar nutrient sprays appear to be effective. Manganese If mancozeb based disease management sprays applied, the young trees should receive sufficient manganese. Iron Common in spring especially if soils are wet. EDDHA-chelated iron applied through fertigation is best treatment option. Iron foliar nutrient sprays not as effective. Slide 22

COPPER DEFICIENCY Slide 23

IRON DEFICIENCY Slide 24