Companion crops or mixed crops are the crops grown generally to avoid diseases and pest attacking the main crop.  The companion crops attract the pests that attack the main crop, in turn maintaining the quality and quantity of yield.  This helps in reducing the man power and extra costs incurred on pesticides or insecticides.
Banana, Soyabean and Chrysanthemum can be grown together for this purpose.
Take 20 liters of Cow urine without dung in it.  Mix Calamus, Harda, Ajwain, Clove, Dry Ginger, Pepper, Mustard, Vayvidang,Turmeric  and powder.  Add a kilo of this powder to Cow urine. 1 kilo of Neem Pinnakku, 100g, Pongamia seeds, 50g, Castor seeds should be powdered and added.  Soak for a week.  Mix a litre of this liquid with 10 liters of water.  As the days go, its potency keeps increasing.  This can be mixed with PanchaGavya and Gunapa water and poured to Banana and Coconut trees.  This can be applied for all skin problems and then bath taken.
If cow urine is sprayed before 10 in the morning or after 4 in the evening once in 8 days, it gets cured.  It also stops the betel nut and coconut fruit drop.
Drumstick and Plantains can be planted with Papaya.  Plant a Banana or Drumstick between two Papaya saplings.  Remaining areas can be used to plant Chendumalli (Tamil), Corn, ThattaiPayaru (Tamil), Agase and vegetables.
Patchouli  grows under the shade of trees.  It needs clay soil.  It can be planted along with Coconut, Rubber and Plantain trees.
Plant Agathi (Sesbania Grandiflora) trees near Banana trees.  Keep cutting Agathi branches and feed cattle.  When this tree is nearby, plantains give good yield.  Agathi absorbs Nitrogen from atmosphere and stores it in its roots.  No other plant can compete with it in this work.  Any plant can be grown under Agathi with benefits.  Gourds, Bitter gourd and Snakegourd creepers can be grown with more yield under Agathi.  Even Betel plant can be made to spread under Agathi.