When to Spray Raspberries

Considerations

• Follow all directions on the packaging material or on the bottle when spraying pesticides onto a raspberry plant. Excess chemicals, chemicals applied at the wrong time or the wrong type of chemical can be as damaging to the harvest as the pests themselves. Wear goggles and gloves when working with pesticides and insecticidal soaps to protect skin and eyes from contact with potentially harmful or irritating chemicals.

Dormant Horticultural Spray

• Apply dormant horticultural oils before the raspberry bush starts putting out flowers and leaves. This helps suffocate any eggs remaining from insect pests the previous growing season and stops the growth of fungi as well. Spray dormant horticultural oils onto the raspberry bush when the tips of the buds are green, recommends the University of Missouri Extension website. Liquid lime sulfurs and delayed horticultural oils help control anthracnose and red-necked cane borers.

During Bloom

• Apply pyrethrin and rotenone-containing pesticides when the raspberry bush is beginning to bloom, according to the University of Missouri Extension. These chemicals are used to control red-necked cane borers and tarnished plant bugs, among other insect pests. A variety of other chemicals can be used to kill pests like the raspberry fruit worm during bloom as well, including pyrethrin and rotenone, as well as carbaryl or neem. Use the chemicals that best fit the plant's needs.

Before Harvest

• Between the time the raspberry finishes blooming and harvest, there are a variety of pest problems that can arise, including issues with various beetles like the Japanese beetle and tarnished plant bugs. Apply sprays every two weeks that contain malathion to control both beetles and tarnished plant bugs. For the control of beetles only, carbaryl, pyrethrin and rotenone work, while tarnished plant bugs alone can be controlled by sprays containing esfenvalerate or with insecticidal soap.