Identification, Biology, & Control of Aboveground Pests in FL Citrus January 23, 2019 • What is IPM?
• What kind of information do you need to develop an IPM program?
Managing pests effectively requires knowledge of their population, phenology, and host association(s) Citrus Production in FL
• Perennial crop • Historically stable ecosystem regarding insect management • Low insecticide inputs prior to ACP • Retention of beneficial species (e.g. lady beetles) within/near crops • More cases of successful biological control than any other cropping system
• ACP + higher insecticide inputs: • T.B.D. Introduction of invasive citrus pests
1964- Diaprepes root weevil
1993- Citrus Leafminer (CLM)
1995- Brown citrus aphid
L. Buss UF/IFAS
1998- Asian citrus psyllid (ACP) Arthropod Pests Affecting Florida Citrus Production
Vedalia lady beetle (Rodolia cardinalis) • Introduced into California in 1888 • First outstanding success in the field of classical biological control • Successfully repeated in Florida in 1899
Cottony cushion scale (Icerya purchasi) Arthropod aboveground impacts on citrus
• Fruit damage • Cosmetic vs destructive damage • Foliage damage • Reduces photosynthetic capacity • Reduces new growth • Disease vectors • Insects that move diseases between hosts Fruit Damage Direct damage to fruit Damage to peel • Feeding reduces fruit quality, • Largely cosmetic shape, or size • Problem for fresh market • Reduction in yield or cause fruit to drop • Problem for fruit grown for fresh & processed markets
Damage from leaf-footed bug feeding. Thrips feeding damage on peel.
Weeks UF/IFAS CREC UF/IFAS CREC Stinkbugs and Leaf-footed bugs
Weeks UF/IFAS CREC Weeks UF/IFAS CREC Weeks UF/IFAS CREC Weeks UF/IFAS CREC
Use piercing-sucking mouthpart to puncture fruit & feed. Feeding holes create openings for secondary pests/pathogens to enter including bacteria, fungi, and other insects.
Weeks UF/IFAS CREC Rust mites Predominant arthropod pest of fresh & processed citrus in Florida Citrus rust mite Pink citrus rust mite (Phyllocoptruta oleivora) (Aculops pelekassi)
UF/IFAS CREC UF/IFAS CREC Rust mite damage to citrus • Damage • Feeding injury • Russeting of fruit & leaves • Mild to severe distortion of new leaf growth • Brown lesions on lower surfaces & along midribs of mature leaves • May produce mesophyll collapse, Leaf distortion on new growth chlorosis, and leaf drop Citrus rust mite Phyllocoptruta oleivora (Ashmead)
UF/IFAS CREC UF/IFAS CREC
Rust mite development
• Females lay 2 eggs/day • ~30 eggs in a lifetime
• Egg adult in 6 days
• Adult male longevity approx. 6 days
• Adult female longevity approx. 14 days Citrus rust mite seasonality Phyllocoptruta oleivora (Ashmead)
UF/IFAS CREC CRM populations peak in early summer, then again at a smaller scale in mid- late fall depending on weather.
0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Pink citrus rust mite Aculops pelekassi (Keifer)
UF/IFAS CREC UF/IFAS CREC PCRM damage to fruit appears as bronzing all over because it is done early in the fruit’s development. Pink citrus rust mite (PCRM) Aculops pelekassi (Keifer)
UF/IFAS CREC
PCRM populations peak in mid spring/early summer. Populations build up on flowers & leaves prior to feeding on fruit.
0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Early in the season, pink citrus rust mites are more prone to damage leaves than the citrus rust mite Natural enemy complex for rust mites
Phytoseiidae Stigmaeidae
A. Pelegrin
Citrus rust mites Tydeidae Cheyletidae
E. McDonald
Other predacious arthropods: Disease lady beetles, ants, spiders, (next slide) lacewing larvae….
Phytoseiid image: http://keys.lucidcentral.org/keys/v3/phytoseiidae/key/phytoseiidae/Media/Html/mites.htm Tydeid image: https://de.wikipedia.org/wiki/Datei:Yellow_mite_(Tydeidae),_Lorryia_formosa.jpg Hirsutella thompsonii Fungal pathogen of mites, biological control for rust mites in citrus Control of CRM by Hirsutella Action thresholds for control of rust mites • Processed fruit • 10 rust mites / 2 cm2 • Controlled with 1-3 oil or miticide applications/season
• Fresh fruit • 2 rust mites / 2 cm2 • Controlled with 3-5 miticide applications/season Citrus mealybug Planococcus citri • Most commonly found in spring and early summer • Prefer sheltered locations • Females lay 300-600 eggs
• Damage • Feeding causes cosmetic damage to fruit • Produce large amounts of honeydew, leads to problems with sooty mold • Can cause heavy fruit drop in grapefruit • Cultivars most affected: grapefruit, navals, valencia Natural enemies of citrus mealybug
• Mealybugs generally occur at low levels and are kept in check by three natural enemies: • Cryptolaemus montrouzieri • Lady beetle • The “mealybug destroyer” • Found in groves May-June • Entomophthora fumosa • Fungus • Prevalent after summer rainy season starts • Leptomastidae abnormis • Hymenopteran parasitoid Various species of lady beetles (Coccinellidae) Cryptolaemus montrouzieri contribute to the - “mealybug destroyer” mortality of several - Efficient predator of mealybugs despite citrus pests. the waxy covering - Nymphal stages LOOK like mealybugs - Can be purchased for release, but there are drawbacks…
Nymph Adult Control of Mealybugs
• Effective products for mealybugs have negative impacts on beneficial insect populations • Insecticides should ONLY be applied to severe infestations • Applications are most effective when applied before mealybugs have settled between fruit clusters • Fruit clusters serve as shelter from management actions BUT naturally occurring predators can often reach these locations Scale insect pests of citrus • Several species of ARMORED SCALES can be problematic • Red scale, purple scale, Chaff scale • Scale insects in Florida have historically been under biological control by a large number of natural enemies • Not currently considered key pests in the development of pest management programs
D. Papacek http://thecitrusguy.blogspot.com/2012/05/citrus-with-some-mussel.html “Secrets to success” for biological control of scale insects • Adult scales are sessile- either VERY slow moving or not moving at all • High number of offspring to support natural enemy population growth • Populations tend to be concentrated easy for natural enemies to find
Aggregation of red scale on green fruit Florida red scale Chrysomphalus aonidum • Damage • Feeding occurs on leaves, green twigs, and fruit • Feeding causes discoloration at the feeding site UF/IFAS CREC
UF/IFAS CREC UF/IFAS CREC Florida Red Scale (Chrysomphalus aonidum)
• Red scale now under biological control by parasitic wasps released in Florida (Aphytis wasps)
• Good example of successful classical biological control Florida red scale • Left: FRS Adult Female with Cover Lifted • Lower left: 3rd instars of Aphytis holoxanthus on adult female scale • Below: 5 fresh pupae of Aphytis holoxanthus under FRS cover Purple scale Lepidosaphes beckii
• Once major pest of fruit, leaves, and twigs
• Populations are highest in late spring/early UF/IFAS CREC summer • Parasitoid (Aphytis lepidosaphes) introduced in 1950s to manage
Parasitoid emergence hole
UF/IFAS CREC Chaff scale Parlatoria pergandii • Often found on trunk and inner canopy • Fruit feeding causes spotting • Slow rate of reproduction + parasitoid Aphytis hispanicus historically kept UF/IFAS CREC populations low
UF/IFAS CREC Thrips • Flower thrips • Greenhouse thrips • Frankliniella bispinosa • Heliothrips haemorrhoidalis • Frankliniella kelliae • Chili thrips • Orchid thrips • Scirtothrips dorsalis • Chaetanaphothrips orchidii • Danothrips trifasciatus
L. Buss UF/IFAS UF/IFAS CREC
Thrips move between plants, making them a huge challenge to manage. Thrips populations can reach high numbers in flowers (semi-protected)& lead to fruit damage F. bispinosa collected from 20 open flowers/rep in March 2001 (Hillsborough Co.)
Variety Adults Larvae Murcott 604 203
Murcott 815 379
Murcott 602 611
Rhode Red Valencia 2,166 1,696
Rhode Red Valencia 2,749 1,488
Rhode Red Valencia 2,468 855
Rhode Red Valencia 2,061 1,070 Control of F. bispinosa on ‘Navel’ Application Mean no. % yield Treatment Insecticides Rate date fruit/m3 increase
Chlorpyrifos 4EC 7.01 L 14 Feb 1 34.2a 43 Formetanate 1.4 kg 1 Mar hydrochloride 92 SP
Dimethoate 4 EC 8.18 L 14 Feb 2 33.9a 42 Formetanate 1.4 kg 1 Mar hydrochloride 92 SP Formetanate 3 1.4 kg 15 Feb 27.9b 17 hydrochloride 92 SP
control n/a -- -- 23.9c --
Childers. 1992. J. Econ. Entomol. 85: 1330-1339 1921 The Citrus Industry 2(3): 19
J.R. Watson 1940 The Citrus Industry 21: 5, 8-9, 12-13, 17
“…the so-called thrips marks are caused by the young fruit being rubbed against leaves and twigs…not by thrips.” (W.C. Thompson) Does F. bispinosa cause scarring damage to ‘Murcott’ fruit? Thrips caging study on ‘Murcott’ blooms Outcome of caging study:
Caged study- 35 days after caging
UF/IFAS CREC
No thrips 10 thrips 25 thrips
Thrips feeding damage on ‘Murcott’ fruit
No Economic Injury Level set
UF/IFAS CREC UF/IFAS CREC Orchid and Greenhouse Thrips
• Cause rind blemishes on developing fruit, in particular “ring spotting” • Develop in protected areas (under calyx, between touching fruit) UF/IFAS CREC • Primarily a problem on red grapefruit varieties but can occur on white grapefruit varieties as well
UF/IFAS CREC UF/IFAS CREC UF/IFAS CREC
Ring scarring where fruit in clusters were touching Monitoring Orchid and Greenhouse thrips
• Examine interior clusters of red grapefruit when fruit are beginning to touch • Use 10x hand lens to search for thrips (larvae and adults) on fruit where touching • If most clusters sampled contain thrips, then insecticide application may be justified •This damage is cosmetic in nature and does not affect internal fruit quality Chili Thrips (Scirtothrips dorsalis) • Recently introduced pest in Florida (2005) • Damage leaves and scar fruit
Host Plants: Over 150 host plants including banana, beans, chrysanthemum, citrus, corn, cotton, cocoa, eggplant, ficus, grape, grasses, holly, jasmine, kiwi, litchi, longan, mango, onion, peach, peanut, pepper, rose, soybean, strawberry, tea, tobacco, tomato, viburnum, etc. Chili Thrips damage
Rose Pittosporum Ligustrum (Privet)
Indian Hawthorn Schefflera Strawberry Scirtothrips spp. (Thysanoptera: Thripidae)
S. aurantii Faure - (South Africa)
S. dorsalis Hood – (Japan & Africa)
S. citri (Moulton) – (California & Arizona) Scirtothrips citri (Moulton) Foliage Pests
• Primarily concerned with protection of foliage on young trees • On mature trees, a few pests are occasionally problematic (i.e., spider mites) • Pest problems typically associated with new flush Young Trees
Goal: Optimize tree growth and vigor to bring trees into production within 3-4 years after setting Young tree pest problems
UF/IFAS CREC Citrus leafminer (CLM)- Phyllocnistis citrella CLM history in Florida
• First recorded in Homestead in Spring 1993 • By December it spread up to the Georgia border Pupal stage 6-22 days Citrus Leafminer Egg 2-10 Lifecycle days
4 larval instars 5-22 days
CLM can also cause damage to green twigs and in rare cases cause mining on fruit surface Seasonality of CLM in Florida
• overwinter as adults with no reproductive diapause • very low populations exist throughout winter months on the low levels of new flush being produced • with warmer weather, CLM produce more offspring more rapidly • populations build up to noticeable levels when the summer flush occurs (usually May to June) Mean percent damage 100 10 20 30 40 50 60 70 80 90 0
3/31/06 Bearing citrus 2006
4/30/06
5/30/06
6/29/06 D a t e
7/29/06
8/28/06
9/27/06 L e a f
d a m
10/27/06 a g e Mean percent damage 100 10 20 30 40 50 60 70 80 90 Non 0
3/31/06 - bearing citrus 2006
4/30/06
5/30/06 D a t e
6/29/06
7/29/06
8/28/06
9/27/06 L e a f
d a m a g e Importance of CLM Damage
• Damage alone not significant on mature trees (New flush : Canopy) • Damage on non-bearing trees can reduce tree growth • Increased time to bring trees into production Canker / CLM Relationship
• Canker incidence can be up to 50% higher in groves where CLM damage is abundant (Sohi and Sandhu, 1968) Choice & Timing of Pesticide Applications Non-bearing/young citrus • soil-applied imidacloprid application is the best option for preventing CLM damage (current UF/IFAS recommendation) • applications should be made 10-14 days prior to anticipated flush • expect about 8 weeks of control • soil-applied imidacloprid just prior to summer flush and again just prior to the fall flush should provide control of CLM during this peak time for CLM damage • may also provide control of Asian citrus psyllid during these times as well Choice & Timing of Pesticide Applications Bearing citrus • preventing damage on bearing trees for canker management much more difficult • must rely on foliar applications if control warranted • there are no soil-applied systemic insecticides available for CLM control on large, bearing trees • as a general rule, there have never been any soil-applied systemic organophosphate or carbamate insecticides shown to provide effective control of CLM damage • this includes aldicarb (Temik)*, dimethoate, oxamyl (Vydate), metasystox (MSR)
*Temik no longer registered for use in citrus Control of Damage by Citrus Leafminer
Soil imidacloprid application: Sept. 4; Foliar applications: Sept. 18 Control of Damage by Spintor Agri-mek + oil
Citrus Leafminer Untreated 60
50
40
30
20
Percent leaf damage 10
0 June 6 June 13 June 21
Foliar treatments applied May 19 Timing of application for leafminer control [FOLIAR APPLICATIONS]
13 days from general budbreak is earliest time for application
Last potential date for leafminer application is 31 days after budbreak • Promoting winter flush may result in higher CLM populations earlier in the season • hedging and topping • excessive irrigation • fertilization regimes
Effects of cultural practices on CLM populations Biological Control of Citrus Leafminer Ageniaspis citricola: Imported into Florida from Australia in 1994
BEFORE intense ACP management, parasitism rates up to 86%were observed late in the season.
NOW-? Use of Pheromones in Leafminer Management
Non-pesticide approaches to CLM control– Previous lecture by L. Stelinski
http://cisr.ucr.edu/images/citrus_laef_miner_1.jpg Aphids Aphids
• Depend on newly expanding leaves for their development • Leaf curling • Large amounts of honeydew (blocks photosynthesis) • Treatment warranted on young trees when > 50% of new foliage is infested Brown Citrus Aphid (BCA) Toxoptera citricida
Vector of citrus tristeza virus *CTV locally absent Aphid predators! Pseudodorus clavatus Green lacewings Syrphid fly Lady beetles Larvae predacious Larvae are predacious Adults & larvae predacious
J. Penney https://commons.wikimedia.org/wiki/File:Harmonia_axyridis_larvae_2.jpg
B. Newton
M. Quinn M. Quinn Cycloneda sanguinea Harmonia axyridis
Drees https://www.treknature.com/gallery/photo269910.htm Citrus Whitefly, Dialeurodes citri •Serious pest in the 1900-1930’s • No longer a serious problem thanks to introduced parasitoid, predatory arthropods, and parasitic fungi
FDACS-DPI Citrus whitefly eggs Whitefly nymphs- translucent, produce Both male and female adults are large amounts of honeydew (1st instar winged. has legs, absent in later instars) Natural Enemies of Citrus Whitefly Exotic parasitoid of Citrus Whitefly, Encarsia lahorensis
Successfully established in Florida in 1977
Whitefly nymph with parasitoid larva and pupa Whitefly Fungi Effective with the right environmental conditions Copper sprays inhibit growth of these “friendly fungi”
Aschersonia spp. Aegerita sp. Foliage pest concerns in mature trees
• Pests that reduce the overall health of the tree • Cause leaf and/or fruit drop • Produce honeydew, promoting sooty mold development Spider Mites Texas Citrus Mite Citrus Red Mite (Eutetranychus banksi) (Panonychus citri) Spider Mites
• Dry conditions favor rapid population growth • Natural enemies exist, but can’t keep up with populations under dry conditions • Highest populations September – May (dry period) • 5-10 spider mites per leaf is action level for treatment if populations are not in decline • Higher percentage of males indicates population declining Leaf drop caused by spider mites (January) Females (Short legs) Male (long legs)
Many females, eggs present, few males = population rapidly growing Scale pests of foliage
Brown Soft Scale, Coccus hesperidum
Black Scale, Saisettia neglecta
Cottony Cushion Scale, Icerya purchasi Green scale, Coccus viridis Honeydew from scale insects deposited on leaves = sooty mold Why do many Hemipterans produce honeydew?
• too much water can be a bad thing • mechanism to cope with foods high in water content
Scale insects psyllids Foregut Temporary storage and grinding of food
Midgut Digestion & absorption of nutrients into body Alkaline pH ≥ 7
Hindgut Re-absorption of water, salt & other nutrients before excretion of (dry) nitrogenous waste (frass) Insect Digestive and Excretory Systems honeydew producers
FC = filter chamber; used to pass water directly out the rectum thus concentrating plant sap before it is absorbed into the insect body Insects and Mites associated with plant diseases
Brief overview of biology… Asian citrus psyllid – Diaphorina citri
First found in Florida June 1998 Citrus Greening Disease Asian Citrus Psyllid Distribution (FL)
• First detected in dooryard citrus trees in south Florida in 1998 • subsequent finds in nursery plants (orange jasmine [Murraya paniculata]) in discount stores throughout the state • psyllid well established in primary citrus growing areas of FL and cannot be eradicated
Picture taken 1.4.19 in CREC groves The “Home Depot” Effect
After Asian citrus psyllid colonized SE Florida (red), it moved on Murraya paniculata to other counties very rapidly. Rapid movement made eradication unfeasible Found in SE areas of Texas and Mexico and CA in 2008 Asian Citrus Psyllid (ACP)
5 nymphal stages
10 generations / year
Life cycle takes 15-47 days
egg adult in 2 weeks at 75-80°F Adult ACP
• 3-4 mm in length • mottled wings • Adult psyllids can feed on both new and mature leaf flushes; prefer young leaves • When young leaves not available, adult psyllids are found on underside of mature leaves feeding on leaf midvein • Mean longevity of females increases with decreasing temperature within 59-86°F / 15-30°C Adults gather at newly emerging growing tips and on young flushes, feed and mate Factors affecting psyllid populations
The two main factors regulating psyllid population growth are:
1.Temperature 2.New leaf flush (resource availability) Asian Citrus Psyllid Eggs
Adults oviposit ONLY on young leaf flush
Eggs are about 0.3 mm long and almond shaped
Eggs are pale when deposited, turn yellow then orange as they mature. Often difficult to see without hand lens * * * * Duration of EGG STAGE (in days) and HATCH SURVIVAL
Temp (°F/°C) Days to hatch Survival 50°F / 10°C 0 0 59°F / 15°C 9.74 ± 0.23 84.5% 68°F / 20°C 7.03 ± 0.11 89.4% 77°F / 25°C 4.15 ± 0.07 95.5% 82°F / 28°C 3.46 ± 0.09 96.2% 86°F / 30°C 3.29 ± 0.06 93.2% 91.4°F / 33°C 0 0
Data from Liu & Tsai, 2000. Ann. Appl. Biol. 137:201-216. Psyllid developmental times (in days) Temp (°F/°C) Egg to adult 50°F / 10°C 0 59°F / 15°C 49.3 ± 0.4 68°F / 20°C 28.8 ± 0.5 77°F / 25°C 17.0 ± 0.2 82°F / 28°C 14.1 ± 0.2 86°F / 30°C 16.3 ± 0.3 91.4°F / 33°C 0
Data from Liu & Tsai, 2000. Ann. Appl. Biol. 137:201-216. Asian Citrus Psyllid Nymphs
• 0.3 mm long in the first instar
• 1.6 mm long as fifth instars
• Nymphs are yellow in color with red eyes and visible wing pads in larger nymphs Asian Citrus Psyllid Nymphs • early nymphal stages easily mistaken for aphids • white carbohydrate secretions provides an easy means of distinguishing from aphids at a distance. Nymphal developmental times (in days)
Temp (°F/°C) Total nymphal stages Survival (%) 50°F / 10°C Failed to develop beyond 0 3rd instar 59°F / 15°C 39.6 ± 0.3 61.9 68°F / 20°C 21.8 ± 0.4 69.8 77°F / 25°C 12.8 ± 0.2 75.4 82°F / 28°C 10.6 ± 0.2 83.9 86°F / 30°C 13.0 ± 0.3 73.7 91.4°F / 33°C Failed to develop beyond 0 4th or 5th instar Data from Liu & Tsai, 2000. Ann. Appl. Biol. 137:201-216. Low temperature developmental thresholds
1st instar 53°F (11.7°C)
2nd instar 51°F (10.7°C)
3rd instar 50°F (10.1°C)
4th instar 51°F (10.5°C)
5th instar 52°F (10.9°C) Effects of Cold Weather on Psyllid Populations January 2-3, 2008 CREC Research Grove 8-10’ ‘Hamlin’ orange Evaluating psyllid mortality • Caged 600 psyllids (30 psyllids/tree) • Cages placed in plots with and without freeze protection (irrigation) • Inside vs outer canopy Factors Evaluated
• Freeze protection vs. no freeze protection • Effects of location of psyllids in tree canopy • Recorded leaf temperatures and trunk base temperatures every 2 hours • Data loggers within cages recorded temps every 15 mins. • Weather station data also collected CREC Jan 3, 2008 (8:00 AM) CREC Temps (Jan 2-3, 2008)
10+ hrs below freezing Effects of Freeze Protection on Psyllid Survival
F = 3.55 P = 0.076 Mortality of Psyllids Located Inside and Outside Canopy
F = 2.31 P = 0.1455 Overall psyllid mortality from freezing Average mortality rate: 60.8%
Minimum mortality observed: 20.7% • Lowest mortality in freeze protection plots • With no freeze protection lowest 41.2%
Maximum mortality observed: 86.8% Conclusions • At CREC location sustained freezing temperatures reduced psyllid populations an average of 60%
• Psyllid mortality likely to vary by location based on duration and intensity of cold
• Cold temperatures in the citrus growing regions of Florida are not enough to reduce the need for early season psyllid control Psyllid feeding damage In the absence of the greening pathogen, psyllid control previously targeted young trees to protect new growth from damage that results in reduced tree growth. Dieback of new growth Witches broom effect Psyllid nymphs produce waxy secretions similar to aphid or scale insect honeydew Sooty mold - growing on sticky residues from secretions from psyllid nymphs Monitoring Psyllid Populations Important to monitor when new flush is available Critical time is spring and fall when temperatures are cooler and flush is abundant Check expanding terminals for aggregations of psyllids
Adult psyllids found on underside of leaves near leaf midvein when no new flush is available Monitoring Psyllid Populations Eggs tucked away in very young, newly forming leaves and leaf buds. Monitoring Psyllid Populations
Inspect new leaf and shoot flushes of citrus and citrus relatives such as orange jasmine, Murraya paniculata. Look for white honeydew and leaf distortion on new leaf flush and shoots. Biological Control of Psyllids
There are numerous natural enemies of psyllids present that suppress psyllid populations, especially in the summer and fall
Use of broad spectrum foliar insecticides will present a problem in maintaining populations of the natural enemies of psyllids and other potential pest species Natural Enemies of Juvenile D. citri in Florida
Ladybeetles (Coccinellidae) Spiders Curinus coeruleus Hibana velox (Anyphaenidae) Cycloneda sanguinea Chiracanthium inclusum (Clubionidae) Exochomus childreni Hentzia palmarum (Salticidae) Harmonia axyridis Oxyopes sp. (Oxyopidae) Olla v-nigrum Hemiptera (Anthocoridae) Green Lacewings (Chrysopidae) Orius sp. Chrysoperla rufilabris Ceraeochrysa spp. (2 - 3) Ants (Formicidae) Dorymyrmex bureni Brown Lacewings (Hemerobiidae) Pseudodmyrmex gracilis Micromus posticus Parasitoids Hoverflies (Syrphidae) Tamarixia radiata Allograpta obliqua Biological Control: Olla v-nigrum
J. P. Michaud Biological Control: Harmonia axyridis Multicolored Asian ladybeetle “Classical” Biological Control Tamarixia radiata • External Parasite • Originally from India • Mass reared & released by FDACS • Variable incidence in Florida Tamarixia radiata: life stages
Adult laying egg Egg attached to abdomen of Adult finding host ACP
Larva attached to Pupa- will emerge underside of ACP, through body of consuming ACP internal tissues http://www.fftc.agnet.org/library/article/tn2001005.html#6 Tamarixia Survey 2006-07 (old, pre-ACP area-wide management attempts)
• surveyed major citrus growing areas
• establishment of Tamarixia?
• parasitism rates? Tamarixia survey 2006-07 average parasitism rates less than 20% throughout most of the season
100 C 80
60 parasitism (%) parasitism
40 T. radiata T. 20
0 M A M J J A S O N D J F M A
2006-2007 Additional Parasitoid Introductions
• Diaphorencyrtis aligarhensis • Encyrtidae • Originally released along with T. radiata; failed to establish • Additional releases made with parasitoids from geographic regions with climates more similar to FL Chemical Control of the Asian Citrus Psyllid
Recommendations updated annually in Citrus Production Guide*
*Current chapter: https://crec.ifas.ufl.edu/media/crecifasufledu/extension/ plant-pathology-/florida-citrus-production-guide/pdf/ACP- and-Leafminer.pdf Soil-applied Insecticides for Psyllid Control
Young trees (< 6-8 feet tall)
• Soil applied systemic insecticides are most effective (imidacloprid, thiamethoxam, clothianidin) • must be applied about 2 weeks prior to flush for best results • in sandy soils, can be washed away if heavy rains occur with 12 -24 hr post treatment • have fewer negative effects on natural enemy populations
Foliar-applied Insecticides for Psyllid Control
Use on both young and mature trees: • best to target psyllids before new flush present •Control adults before eggs laid • typically broad-spectrum products • most have negative effects on natural enemies •Will discuss in more detail later (next lecture) Brevipalpus mites and Citrus Leprosis Tenuipalpidae
• Over 622 species in 26 genera worldwide • False spider mites, flat mites • Primarily found in tropical/subtropical areas • Genus Brevipalpus most important economic group
Egg 50-60/female
Larva Adult Female Adult Male
Teliochrysalis Photochrysalis
Deutonymph Protonymph
Deutochrysalis Comparative developmental rates, egg production and adult longevity of Brevipalpus phoenicis and Panonychus citri at 270 C (Duration in days) B. phoenicis P. citri
Egg 6.0 3.4 Larva 4.8 1.9 Protonymph 4.8 1.6 Deutonymph 4.9 2.3 Egg-Adult 20.7 12.0 Adult Longevity 20.4 - Host Oroxylum indicum Citrus sp. Authors: Beavers & Hampton 1971; Lal 1978; Saito 1979 Brevipalpus californicus, B. obovatus and B. phoenicis Two problems: • Mites can develop to large numbers on various host plants. They have toxic saliva that can result in feeding injuries to citrus and other economic crops. • Mites are vectors of one or more unassigned Rhabdoviruses in citrus, coffee, passion fruit, orchids and numerous woody ornamental plants. Brevipalpus spp.
Examples of direct feeding damage – The following images ARE NOT LEPROSIS
Leprosis
• Problem on sweet orange varieties • Caused by virus that is not systemic in plant • B. phoenicis is the only confirmed vector • Miticide costs on Brazilian citrus exceed 90 million US dollars per year (Omoto 2000) • Currently not in Florida (is present in Mexico) Citrus Leprosis (symptoms) • Chlorotic leaf lesions becoming brown with or without necrotic centers • Flat or slightly raised necrotic areas on twigs and leaves • Flat or depressed lesions on fruit with concentric patterns and gumming • Abscission of leaves and fruit and twig dieback due to extensive lesion development Leprosis: Fruit Lesions Leprosis : Fruit Drop Sharpshooters and Citrus Variegated Chlorosis Citrus Variegated Chlorosis • Causal agent Xylella fastidiosa, a xylem limited bacteria • Found in Brazil, Argentina, Paraguay, and more recently identified in Costa Rica • Transmitted by sharpshooter leafhoppers • Infects most citrus cultivars Next Lecture…
• Insecticides and modes of action
• How to develop a comprehensive pest management program in the presence of ACP/HLB