Pests on Ornamental Plants

 

Plant: Hibiscus rosa sinensis  (Bunga Raya)

Pests: 1. Red cotton bug

           2. Weaver ants

1. Dysdercus cingulatus
   (Red cotton bug)

Damage & Symptom

-Adult and nymph sucking sap on stem and fruit

-Stunted growth and holes on fruit  

Control Method

-Chemical control by apply Sevin or Gamma BHC with 0.1% active ingredient, Carbaryl.

-Biological control by:

1.Allowing chickens to roam in gardens in small plot areas helps to control

    these insects.

2.Two parasitoids namely Acaulona peruviana and Paraphoronta peruviana have

    been reported to reach a high degree of parasitization of the nymphs.

 

 2. Ocoephylla smaradgina 

     (Weaver ant) 

Damage & Symptom

- Ants are a secondary problem on the hibiscus plant that carry aphids' eggs onto it. The reason the ants do this is because they are after the honeydew that aphids make from ingesting plant sap.

- Ants farm and herd aphids so they can lap up the honeydew the aphids excrete on the leaves. Ants will guard the aphids they bring onto the plant, even fighting off ladybugs. A side effect of the aphids is black sooty mold. When spores of the mold land on the honeydew, they quickly spread over it.

Control Method

- For effective control against ants, you have to remove aphids and other honeydew-secreting pests from your hibiscus. Spray a jet of water from a hose over aphids or wipe a cloth soaked in rubbing alcohol over infestations. Alternatively, spray insecticidal soap or neem oil over infestations.

- You can also apply a pyrethrin-based insecticide that is made from chrysanthemum extracts over infestations for nontoxic control over the pests. However, the insecticide kills beneficial insects, including bees and ladybugs. Sticky barriers applied at the base of your hibiscus help reduce ant infestations.

Plant: Bougainvillea ( Bunga kertas)

Pests: 1. Javanese Grasshopper

2. Leaf Miner

1.Valanga nigricornis

 (Javanese Grasshopper)

 Damage & Symptom

The leaves and soft shoots are eaten from margin inwards leaving irregularly shaped feeding marks. Swarm damage usually results in complete defoliation of the crop.

 Control Method

Contact insecticides have been used to control these pests, either as spot-sprays or blanket treatments usually methamidophos.

 

 2. Liriomyza sp 

    (Leaf Miner)

  

Damage & Symptom

-The maggots mine under the surface of leaves, resulting in the formation of white tunnels.

 -In some related species of these pests, they will chew the leaves giving them a blotchy look

. 

Control Method

-remove any damaged leaves and destroy them.

-Use Bacillus thuringiensis.

 

Plant: Allamanda cathartic (Bunga Loceng)

Pests: 1. Red Spider Mites

           2. White flies

1.  Tetranychus urticae

(Red Spider Mites)

Damage & Symptom 

Damage  parts : Leaves

Symptoms : It lays its eggs on the leaves, and it poses a threat to host plants by sucking cell contents from the leaves cell by cell, leaving tiny pale spots or scars where the green epidermal cells have been destroyed.

Control Method

a) Biological control

The mite's natural predator, Phytoseuilus persimilis, commonly used as a biological control method, is one of many predatory mites which prey mainly or exclusively on spider mites.

b) Chemical control

-Using selective chemicals that are less or not toxic to natural enemies or by using chemicals in selected areas of the crop.

-For example Dimethoate ULV.

-All the chemicals are being tested first before used for the chemical control.

c) Cultural/physical method

-Spider mites thriven in hot, dry conditions. Increasing the humidity level by misting plants can reduce the growth of spider mites. But care should be taken because increasing humidity may increase the possibilities of fungal diseases.

2. Trialeurodes vaporariorum 

      ( White flies)

Damage & Symptom

Damage parts :

 Prefer the underside of leaves to feed and breed

Symptoms :

Larvae and adults pierce and suck juices from plant cells causing reduced photosynthesis and growth, leaf drop and reduced harvest. Larvae and adults excrete honeydew (coveted by ants) which can lead to an unattractive black surface fungal growth called sooty mold. Molds colonize the honeydew reducing photosynthesis and transpiration on leaves and leaving sticky, “dirty” deposits on fruit (unmarketable). They also can transmit many harmful plant viruses.

•Leaf become discoloration (dulling, browning, yellowing, necrosis)

•Leaf distortion (curling, crinkling, stunting)

•Slow and unthriffy plant growth

•Premature defoliation 

Control Method•.

•Remove infested plants away from non-infested plants

•Use a reflective mulch (aluminum foil) under plants (this repels white flies)

•Trap with yellow sticky cards

• Apply labeled pesticides (foliar applications of insecticidal soaps and oils)

•Encourage natural enemies such as parasitic wasps (aphelinid parasitoid, Encarsia formosa (Gahan)) in the garden

•Apply a good steady shower of water to wash them off the plant