CMG GardenNotes #101 IPM and Plant Health Care. Gardening and the Environment. Integrated Pest Management, IPM

Transcription

1 CMG GardenNtes #101 IPM and Plant Health Care Outline: Gardening and the envirnment, page 1 Integrated Pest Management, IPM, page 1 Plant Health Care, PHC, page 2 PIC cycle, page 2 PHC/IPM techniques, page 3 Pest management questins, page 4 Life cycle f a plant, page 5 Gardening and the Envirnment Integrated Pest Management, IPM Yard care and gardening practices may have psitive r negative influences n health and the neighbrhd envirnment. Fr example, turf enhances the envirnment by: Cnverting carbn dixide t xygen. Increasing water infiltratin int the sil. Reducing surface runff and ersin. Reducing dust. Prviding a micr-ecsystem that effectively breaks dwn pllutants. Mderating summer temperatures. Creating a pleasant peple space. On the ther hand, lawn care practices negatively affect the envirnment when grass clippings are mwed r blwn nt the street (water quality prblem), when fertilizers are ver-spread nt hard surfaces, and when the unwarranted use f pesticides ccurs. Several terms (such as Integrated Pest Management, Plant Health Care, Sustainable Farming/Gardening, Best Management Practices and Organic Gardening) are used t describe farming/garden management systems designed t help farmers/gardeners maximize psitive effects and minimize negative effects. Integrated Pest Management, IPM, incrprates a variety f pest management strategies, including cultural and mechanical methds, use f 101-1

2 Plant Health Care, PHC binaturals and pesticides. Objectives include minimizing pest damage, health-related hazards and envirnmental hazards, while maintaining prfitability. Because insect and disease prblems vary significantly frm crp t crp, applicatin f IPM principles is als crp specific. IPM techniques used in an alfalfa field (perennial crp), a wheat field (annual crp), an apple rchard (perennial crp with minimal tlerance fr pest damage) and the landscape (site with multiple plant species and higher tlerance t pests) will be vastly different. The term Plant Health Care, PHC, was cined by the Internatinal Sciety f Arbriculture t define IPM techniques as they apply t tree care and landscape maintenance. Yu will ften find the tw terms (IPM and PHC) used interchangeably. PHC, like IPM, is a hlistic apprach, but specifically t tree and landscape management. The primary bjective is t grw healthy plants and minimize the effects f pests in s ding. Cncepts f PHC include the fllwing: Healthy plants have fewer pests. Many insect and disease prblems nly attack stressed plants. Minimizing stress prevents many cmmn pests. Fr example, Cytspra fungus and mst brers nly attack stressed trees (frm factrs such as sil cmpactin, drught, rt damage and drught). Healthy plants are mre tlerant f pests. Fr example, aphids n shade trees generally d nt warrant management effrts. An imprtant exceptin is that trees that are water stressed (dry sils, nn-established rt systems, limited rt spread, etc.) are intlerant f aphid feeding. Life cycle: Plant needs change with stages in their life cycle. A plant s needs fr irrigatin, fertilizer, pruning, tlerance t pests, etc. cntinually change thrugh the grwth cycles f the plant. PIC cycle: Prblems arise frm a cmbinatin f stress factrs. Fr example, ver-maturity f frests cupled with drught leads t bark beetles in Western pine frests. Sil cmpactin, drught and restricted rting can lead t Cytspra canker disease. The PIC Cycle A basic principle f PHC is recgnitin that plant prblems generally arise frm a cmbinatin f stress factrs. This cncept is called the PIC cycle

3 Predispsing factrs reduce a plant s tlerance t stress. These factrs shuld be cnsidered in plant selectin. Examples f predispsing factrs include: Planting trees in a site where rt spread will be restricted due t sil cmpactin r hardscape features. Planting trees intlerant f wet sils (like crabapples) in heavily irrigated lawns (leads t rt rts). Planting trees susceptible t irn chlrsis in sils with free lime. Failure t structurally train yung trees (predispsing trees t strm damage). Inciting factrs include primary insect, disease, and abitic disrders that attack healthy plants, causing acute stress. Examples include: Sil cmpactin, the mst cmmn stress factr leading t many insect and disease prblems. Planting trees t deep (leads t trunk girdling rts). Drught. Leaf chewing insects, such as caterpillars and sawfly larva. Leaf sucking insects, such as aphids and leafhppers. Bark damage frm lawn mwers. Bark cankers and frst cracks frm rapid winter temperature changes cupled with winter drught. Cntributing factrs include secndary insect, disease, and abitic disrders that attack plants already stressed. They ften lead t the plant s death and frequently cannt be cntrlled. Examples include: Bark beetles and brers (secndary t sil cmpactin, drught, and wind damage). Cytspra fungus (secndary t sil cmpactin, drught, and restricted rting system). Trunk girdling rts caused by planting t deep. Management f cntributing factrs typically needs t be directed at the predispsing and inciting factrs that stress the plant. IPM/PHC Techniques Examples f techniques used include the fllwing: Plant selectin: right plant, right place Select plants t minimize future stress issues fr the site. Sils management Many landscape plant prblems relate t sil cnditins

4 Manage sil cmpactin (lw sil xygen and pr drainage) Manage sil drainage Imprve sil tilth with rutine applicatins f rganic matter Nutrient (fertilizer) management Water and irrigatin management Water plants apprpriately - the water requirement fr plants t survive cmpared t the water needed fr plant grwth may be vastly different. Use plant tlerance t wet r dry cnditins in water management Chrnic, springtime verwatering ften causes r cntributes t the develpment f irn chlrsis symptms. Cultural care Plant at apprpriate time Use varieties with resistance t cmmn pests Use a diversity f plants Plant apprpriately fr gd spacing and air flw Cnsider plant s ptential expsure t sun and wind Use mulch Prune apprpriately Weather influence n plant grwth and pest ptential Cnsider bth high and lw temperatures Cnsider wind and rain effects Cnsider timing f insect activity Mechanical methds t manage pests Cvers and barriers Traps Binaturals fr managing pests Use f predatrs, parasites, disease rganisms, and beneficial nematdes Preservatin is taking steps t encurage naturally ccurring predatrs and parasites. Imprtatin is the purchase and release f predatrs and parasites Pesticides if selected, use the apprpriate pesticide t manage the prblem at the crrect rate and at the crrect time f year

5 Pest Management Questins As part f IPM/PHC, ask the fllwing questins t guide pest management: 1. What is the plant? Crrectly identifying the plant will shrten the list f ptential insects, diseases, and abitic disrders. 2. What is the disrder/pest? Crrectly identifying the disrder/pest will guide effective management ptins. Gardeners ften fail t cntrl pests because they have misidentified the prblems and are applying ineffective management techniques. 3. What type f damage/stress des it cause? In the landscape setting, mst insect and disease prblems are nly csmetic and may nt warrant management effrts. T prtect plant health, management may be needed n sme pests. Fruits and vegetables typically have lw tlerance t insects and diseases. 4. Under what situatins will management effrts be warranted? In prductin agriculture, ecnmic threshlds determine hw much damage can be tlerated befre it becmes ecnmically feasible t treat. Fr example, this may be determined by cunting the number f insects per leaf, the number f insects in a square ft f sil, r the percent f leaves infected. In landscape hrticulture, aesthetic threshlds characterize a relative level f csmetic damage that can be tlerated befre treatment is warranted. This threshld will vary cnsiderably frm individual t individual and frm lcatin t lcatin. Spider mites are an example f a cmmn pest generally kept in bunds by nature. Hwever management effrts may be warranted in situatins where mite ppulatins flare up due t ht weather, drught, dust n plants (interferes with activity f beneficials) r the use f sme insecticides including imidaclprid (Merit) and carbaryl (Sevin). 5. What management ptins are effective n the disrder/pest and when are they applied? Weather While we cannt cntrl the weather, it directly influences the ccurrence f many insects and diseases Cultural Such as watering mre r less Mechanical Such as washing dwn the plant with a frceful stream f water t wash ff pests Binaturals Use f beneficial predatrs and parasites Pesticides Many types 101-5

6 Life Cycle f a Tree A key cncept in PHC includes recgnizing that plant care changes with varius stages f grwth. Failure t relate cultural practices t the life cycle ften leads t reduced grwth and cnfusin abut apprpriate cultural practices. Tables 1 and 2 give an verview f the life cycle f trees. Life cycle f a tree Life cycle f a vegetable (annuals) 1. Nursery prductin 1. Seed germinatin and emergence 2. Establishment phase 2. Seedling grwth 3. Grwth phase 3. Grwth phase 4. Maturity 4. Flwering and fruiting phase 5. Decline phase Table 1 Life Cycle f a Tree Grwth Phase Grwth Objectives Change t Next Grwth Phase Nursery prductin Establishment phase Grwth phase Maturity Tp grwth = selling price Rt establishment Perid f canpy grwth Balance canpy grwth with rt grwth limitatins. Canpy grwth slws as tree matures Balance canpy grwth with rt grwth limitatins. Planting When rts becme established, length f annual twig grwth significantly increases. Grwth slws as tree appraches mature size (fr site limitatins). Minimizing stress n aging trees prlngs tree life. Decline phase Minimize stress levels. Death 101-6

7 Table 2 Influence f Life Cycle n Cultural Practices fr Trees Grwth Phase Irrigatin Water Need Fertilizatin Pruning Pest Tlerance Nursery prductin Establishment Water = Grwth CRITICAL Trees are under water stress due t the reduced rting system. Fertilizer pushes desirable tp grwth. Nne t very little as high nitrgen frces canpy grwth at the expense f rt grwth. Structural training desirable. Heavy pruning slws rt establishment. LOW Culd influence sales. LOW due t drught impsed by reduced rt system. Water = Grwth Grwth Gd tlerance t shrtterm drught. Hwever, shrt-term drught will slw grwth. IF ther grwth factrs are nt limiting, fertilizatin supprts grwth. Structural training sets the tree s structural integrity fr life. HIGH, except in stress situatins. Maturity Gd tlerance t shrtterm drught. Severe drught leads t decline. Need fr fertilizer reduces. Over fertilizatin culd frce canpy grwth that the rts cannt supprt in summer heat and wind. Maturing trees that were structurally trained while yung have minimal needs fr pruning. HIGH, except in stress situatins. Decline Intlerant f drught Evaluate stress factrs as fertilizatin can accelerate stress in sme situatins. Pruning limited t cleaning (remval f dead wd). D nt remve healthy wd n stressed trees. LOW, pests culd accelerate decline. Authr: David Whiting, Extensin Cnsumer Hrticulture Specialist (retired), Department f Hrticulture & LA, Clrad State University. Revised by Mary Small, state Clrad Master Gardener crdinatr, Clrad State University Extensin. Clrad Master Gardener GardenNtes are available nline at Clrad Master Gardener/Clrad Gardener Certificate Training is made pssible, in part, frm a grant frm the Clrad Garden Shw, Inc. Clrad State University, U.S. Department f Agriculture and Clrad cunties cperating. Extensin prgrams are available t all withut discriminatin. Cpyright Clrad State University Extensin. All Rights Reserved. CMG GardenNtes may be reprduced, withut change r additins, fr nnprfit educatinal use. Revised and updated June