Broomrape in Tomato Fields
The parasitic plant Orobanche (broomrape) has become an invasive weed and growing pest in processing tomato fields throughout California’s Central Valley, the major tomato growing region of the United States. Broomrape can take over a tomato field in a season, rendering that field unusable. Without effective weed control products, many tomato fields have been quarantined. The IR-4 Project California has been funding screening of herbicides to control this devastating pest and making progress in finding solutions for growers.
In recent years there have been increases in the number of grape mealybug infestations in the San Joaquin Valley and North Coast vineyards. Mealybugs damage grapes by contaminating clusters with cottony egg sacs, larvae, adults, and honeydew. With the loss of Lorsban® (chlorpyrifos) for control, the IR-4 Project California is funding screening of alternative pesticides for effective control of this challenging vineyard pest.
Naval Orange Worm in Fig Orchards
California ranks first in the nation for fig production, accounting for over 95 percent of the figs grown in the US. In addition to tree nuts, the Naval Orange Worm has become a key pest in figs and control has largely consisted of pyrethroids. Resistance to pyrethroids is increasing and alternatives are needed by fig growers. The IR-4 Project California is funding residue trials to support the registration of Intrepid® (methoxyfenozide) in figs.
Citrus mealybugs can cause a great deal of damage to citrus crops resulting in wilted, distorted and yellowed chlorotic leaves, premature leaf drop, stunted growth, and even death of infested plants. This mealybug is also a common pest on indoor ornamentals and landscape shrubs. Chlorpyrifos has been the industry standard for controlling mealybugs. The IR-4 Project California is supporting efficacy trials on miniroses to find alternatives for mealybug control using biological pesticides and softer chemistries.
Olive Fruit Fly
The olive fruit fly, Bactrocera oleae (Diptera, Tephritidae) was first recorded in California in October 1998 when a single female fly was captured in west Los Angeles. This pest is now established throughout California and the IR-4 Project California is funding the development of the biorational insecticide Sivanto® (flupyradifurone). Funding in 2019 supported efficacy trials located in Butte county near Orland, California.
Kiwi Botrytis Rot
Botrytis fruit rot, also known as gray mold decay, is a soft fruit rot that can result in significant crop losses during kiwi storage. Kiwi growers have relied on Vanguard® (cyprodinil) for gray mold control with few alternative controls. The IR-4 Project California is funding residue trials for Luna Sensation® (trifloxystrobin + fluopyram) which once registered will provide alternative modes of action for botrytis control.
Thrips are the most common insect pest of onion, causing widespread damage. They are found wherever onions are grown in California. Thrips are present every year, but infestations vary widely depending on weather conditions. Both onion thrips and western flower thrips attack onions, and their numbers can vary over the season. Thrips may also transmit iris yellow spot virus, which is an economically significant disease of onions. The IR-4 Project California is funding field residue trials for Beleaf® (flonicamid) to provide onion growers with a resistance management insecticide product.