🍄 Fungal Diseases
Anthracnose
Colletotrichum gloeosporioides
High Risk
Symptoms
- Dark brown/black sunken spots on fruits
- Leaf blight and twig dieback
- Premature fruit drop
- Pink spore masses in humid conditions
✦ Solutions
- Spray Carbendazim 50 WP @ 1g/L or Mancozeb 75 WP @ 2g/L
- Copper oxychloride 50 WP @ 3g/L as protective spray
- Remove and destroy infected fruits and twigs
- Avoid overhead irrigation; improve air circulation
- Pre-harvest bagging of fruits
Wilt (Fusarium Wilt)
Fusarium oxysporum
Very High Risk
Symptoms
- Sudden wilting and yellowing of leaves
- Brown/dark discoloration inside stem
- Root rotting at base
- Complete plant death within weeks
✦ Solutions
- Drench soil with Carbendazim 50 WP @ 1g/L near root zone
- Apply Trichoderma viride biocontrol @ 5g/plant to soil
- Remove infected plants and burn; don't compost
- Avoid waterlogging; ensure good drainage
- Plant resistant or tolerant guava varieties
Algal Leaf Spot
Cephaleuros virescens
Medium Risk
Symptoms
- Greenish-grey, velvety spots on leaves
- Rust-coloured powdery patches later
- Premature leaf fall in severe cases
✦ Solutions
- Spray Copper oxychloride 50 WP @ 3g/L
- Bordeaux mixture (1%) twice a season
- Prune to improve canopy airflow
- Avoid excess nitrogen fertilizer
Styler-End Rot / Fruit Rot
Phytophthora nicotianae
High Risk
Symptoms
- Water-soaked, dark rot at styler end of fruit
- White cottony growth in humid weather
- Fruit shrivels and drops prematurely
✦ Solutions
- Metalaxyl 35 WP @ 2g/L or Fosetyl-Al spray
- Avoid water stagnation around trees
- Mulch around base to prevent soil splash
- Harvest fruits at early maturity stage
Canker (Pestalotiopsis)
Pestalotiopsis psidii
Medium Risk
Symptoms
- Irregular brown cankers on stem and branches
- Tiny black fruiting bodies on bark surface
- Bark cracking and peeling
- Dieback of affected shoots
✦ Solutions
- Prune infected branches 10cm below lesion
- Paint wounds with Bordeaux paste
- Spray Carbendazim + Mancozeb combination
- Avoid wounding trees during cultivation
Powdery Mildew
Oidium psidii
Medium Risk
Symptoms
- White powdery coating on young leaves & shoots
- Leaves curl and turn yellow
- Flower drop reducing fruit set
✦ Solutions
- Sulphur 80 WP @ 2.5g/L or Wettable Sulphur spray
- Dinocap 48 EC @ 0.5ml/L
- Apply Neem oil 5000 ppm @ 3ml/L
- Spray in cool morning hours
🌿 General Fungal Prevention Tips: Maintain proper spacing (6×6m), practice balanced nutrition (avoid excess N), apply mulch to reduce soil-splash, collect and destroy fallen leaves/fruit, use drip irrigation to keep foliage dry, and rotate fungicide groups to prevent resistance.
🐛 Insect & Pest Attacks
Fruit Fly
Bactrocera dorsalis
Very High Risk
Damage Signs
- Pin-prick puncture marks on fruit surface
- Internal rotting of pulp with maggots
- Premature fruit drop
- Fermentation odour from infested fruit
✦ Solutions
- Methyl eugenol traps with Malathion (attract & kill)
- Bag fruits with paper/polythene bags at marble size
- Protein hydrolysate bait spray (Malathion + bait)
- Collect and destroy fallen infested fruits daily
- Spinosad 45 SC @ 0.3ml/L spray as alternative
Guava Moth / Bark Eating Caterpillar
Indarbela tetraonis
High Risk
Damage Signs
- Silken webs with frass on bark surface
- Holes bored into trunk and main branches
- Sap oozing from entry holes
- Branch dieback above bored area
✦ Solutions
- Inject Chlorpyrifos 20 EC diluted into bore holes; seal with clay
- Insert kerosene-soaked cotton wads into holes
- Remove webbing and kill larvae manually
- Paint trunk with Carbaryl 50 WP paste
- Apply sticky tree bands to prevent adult egg-laying
Guava Whitefly
Trialeurodes variabilis
Medium Risk
Damage Signs
- Tiny white insects under leaves, fly when disturbed
- Yellowing and curling of leaves
- Honeydew secretion causing sooty mould
- Stunted growth of young shoots
✦ Solutions
- Imidacloprid 17.8 SL @ 0.5ml/L or Thiamethoxam 25 WG @ 0.3g/L
- Neem oil 5000 ppm @ 3ml/L (organic option)
- Yellow sticky traps @ 15-20/hectare
- Spray undersides of leaves thoroughly
Scale Insects / Mealy Bugs
Ferrisia virgata / Pseudococcus
Medium Risk
Damage Signs
- Cottony white masses on stems and leaf axils
- Yellowing of leaves; honeydew + sooty mould
- Bark encrusted with grey/brown scales
- Fruit malformation and cracking
✦ Solutions
- Dimethoate 30 EC @ 2ml/L or Chlorpyrifos 20 EC @ 2ml/L
- Spray Neem soap solution (5g/L) on colonies
- Introduce natural predator Cryptolaemus montrouzieri
- Scrub scales off bark with stiff brush + lime wash
Red Spider Mite
Tetranychus urticae
Medium Risk
Damage Signs
- Tiny red/brown dots on leaf surface
- Fine silken webbing on underside of leaves
- Leaves turn bronze, dry and fall early
- Worse in hot, dry weather
✦ Solutions
- Dicofol 18.5 EC @ 2.5ml/L or Abamectin 1.8 EC @ 0.5ml/L
- Wettable sulphur 80 WP @ 2g/L is effective
- Strong water jets to dislodge mites
- Maintain soil moisture; avoid water stress
Leaf & Shoot Borer / Psyllid
Trioza vitreoradiata
Medium Risk
Damage Signs
- Pitting and deformation of new leaves
- Pimple-like galls on leaf surface
- Curling and cupping of young leaves
- Terminal shoot damage in young plants
✦ Solutions
- Imidacloprid 17.8 SL @ 0.3ml/L at flush stage
- Systemic insecticide soil drench for young plants
- Remove and destroy galled leaves
- Spray at early morning when psyllids are less active
🐛 General Pest Prevention Tips: Monitor orchards weekly, use pheromone/light traps, practice clean cultivation, plant trap crops, encourage natural predators (birds, parasitic wasps), avoid excess nitrogen that promotes soft succulent growth attractive to pests, and rotate pesticide classes to prevent resistance.
📋 Quick Reference Table
All Diseases & Pests at a Glance
| Disease / Pest | Type | Pathogen / Organism | Key Symptom | Primary Chemical Solution |
|---|---|---|---|---|
| Anthracnose | Fungal | Colletotrichum gloeosporioides | Black sunken spots on fruit | Carbendazim / Mancozeb spray |
| Fusarium Wilt | Fungal | Fusarium oxysporum | Sudden wilting, stem discoloration | Carbendazim soil drench + Trichoderma |
| Algal Leaf Spot | Fungal | Cephaleuros virescens | Velvety grey-green leaf spots | Copper oxychloride / Bordeaux mixture |
| Fruit Rot (Styler-End) | Fungal | Phytophthora nicotianae | Water-soaked rot at fruit tip | Metalaxyl / Fosetyl-Al spray |
| Bark Canker | Fungal | Pestalotiopsis psidii | Brown bark cankers, dieback | Prune + Bordeaux paste + Carbendazim |
| Powdery Mildew | Fungal | Oidium psidii | White powder on young leaves | Wettable sulphur / Dinocap |
| Fruit Fly | Insect | Bactrocera dorsalis | Maggots inside rotting fruit | Methyl eugenol trap + Spinosad |
| Bark Eating Caterpillar | Insect | Indarbela tetraonis | Bore holes in trunk, sap ooze | Chlorpyrifos injection into holes |
| Whitefly | Insect | Trialeurodes variabilis | White insects + sooty mould | Imidacloprid / Thiamethoxam |
| Mealy Bug / Scale | Insect | Ferrisia virgata | Cottony masses on stems | Dimethoate / Chlorpyrifos spray |
| Red Spider Mite | Insect | Tetranychus urticae | Bronze leaves, fine webbing | Dicofol / Abamectin / Sulphur |
| Guava Psyllid | Insect | Trioza vitreoradiata | Leaf galls, shoot deformation | Imidacloprid at new flush stage |
⚠️ IPM (Integrated Pest Management) Approach: Always start with cultural methods (sanitation, pruning, bagging), then biological controls (Trichoderma, Cryptolaemus, traps), and use chemical sprays only when pest/disease threshold is exceeded. Follow label doses strictly and observe pre-harvest intervals (PHI) for all pesticides.